And now, the Republican establishment’s Tea Party-induced headaches may be about to get worse — much, much worse. A stunning new poll released Sunday night finds Christine O’Donnell, a far-right gadfly and chronic debtor who has accused her political opponents of following her home and hiding in the bushes and who has equated lust with adultery, now running three points ahead of Rep. Michael Castle, a nine-term congressman and former two-term governor, in a GOP Senate race that will be settled this Tuesday. O’Donnell, previously known only for waging a series of hopeless, quixotic campaigns, has caught fire in the last few weeks, thanks largely to the Tea Party Express, which has poured money into the state on her behalf, and to a late endorsement from Sarah Palin.

The national implications of an O’Donnell victory on Tuesday would be stark: All of a sudden, a race that Democrats had written off as lost — even Vice President Joe Biden’s son was intimidated out of the race by the moderate Castle and his perceived general election invulnerability — would be theirs for the taking. Until now, every Senate calculation has listed Delaware as a slam dunk pick-up for the GOP. But O’Donnell would make an absurdly easy mark for Democrat Chris Coons, the county official who entered the race when Beau Biden refused to. In essence, Tuesday’s primary is a choice for Republicans between victory and defeat in November — and they seem to be leaning toward defeat.

O’Donnell’s surge is all the more remarkable because Castle and the GOP establishment recognized that it was possible — and tried to nip it in the bud. The warning bells went off almost as soon as little-known Joe Miller scored a completely unexpected upset in Alaska’s Republican primary on August 24, knocking off incumbent Sen. Lisa Murkowski. Miller was aided by a massive infusion of Tea Party Express cash — about $600,000, big bucks for an Alaska race. Castle recognized that with his impeccable establishment credentials, long service in government, and flexible ideology, he could be vilified by the Tea Partiers just as easily as Murkowski. So he and his establishment allies went to work trying to undermine O’Donnell, playing up her baggage and hoping to convince the GOP base to reject her — however grudgingly — in the interest of winning the seat in the fall.

Granted, it’s possible that Castle will still survive. O’Donnell’s lead in Sunday’s poll is a slim three points, 47 to 44 percent, and given the tiny Republican primary universe in Delaware, there’s probably a lot of wiggle room in those numbers. And maybe what is now the very real prospect of an O’Donnell win and its November implications will give just enough GOP primary voters cold feet to save Castle. Indeed, even as the PPP poll numbers were being released Sunday, the conservative Weekly Standard was reporting that O’Donnell had filed a $6.95 million gender discrimination and wrongful termination lawsuit against her former employer, a conservative nonprofit organization, in 2005 and that she had falsely claimed to have done master’s degree coursework at Princeton University in 2003 — a late-breaking revelation that could stall her momentum.

What is clear is that if O’Donnell does prevail, it will represent the Tea Party’s most destructive (to the GOP) triumph yet.

It may not be their only triumph on Tuesday, though. Another new poll released on Sunday, also from Public Policy polling, finds that Ovide Lamontagne, a grassroots conservative favorite, is now trailing the establishment-backed Kelly Ayotte by just 7 points in New Hampshire’s GOP Senate primary. Just a few weeks ago, Lamontagne was stuck in single digits in the four-way race, nearly 40 points behind Ayotte. But the aggressive support of the ardently conservative Union Leader newspaper and an ugly air war between Ayotte and another candidate, Bill Binnie,  has boosted Lamontagne’s standing.

If he does win, it won’t be as disastrous to the GOP as an O’Donnell victory. Lamontagne’s ideology is far to the right, but his resume is a serious one and he knows how to conduct himself in the spotlight. He will be tougher for Democrats to paint as a kook. Still, his ideology haunted him in his last campaign, when he rode a conservative tide to the GOP gubernatorial nomination in 1996 — only to be pigeonholed as an extremist and beaten handily by Democrat Jeanne Shaheen in the general election.

If Ayotte hangs on, the PPP poll suggests, it will be because she’s made some inroads with the Tea Party crowd, which is right now divided evenly between her and Lamontagne. But the momentum is with Lamontagne, and if he does pull it out, his party’s November prospects will be shakier than they’d be with Ayotte as the nominee.

The GOP establishment will undoubtedly spend the next two days knocking itself out to prevent upsets in both states, particularly Delaware. Of course, that may end up putting the insurgents over the top.

Republicans, who have an outside chance of capturing the majority in the Senate in November, see Castle as their best chance of winning the seat long held by Vice President Joe Biden. The moderate Castle is a former governor and has been the state’s lone congressman since 1993.

But O’Donnell, who has lost twice in statewide races, won’t be cowed.

“We cannot elect any more liberals to Washington, D.C., especially ones who wear the banner of being a Republican. It is an honor to be a Republican,” she told supporters.

Establishment Republicans have been relentless, calling O’Donnell unelectable, a fraud and a liar. But in a challenge to the GOP leadership and in a boost to O’Donnell, GOP Sen. Jim DeMint of South Carolina just came out with an endorsement saying she will “stand strong for the principles of freedom.”

This weekend, Delaware Republicans set about knocking on 10,000 doors, making tens of thousands of phone calls and flooding mailboxes with fliers that explain both candidates’ records. In a primary that could draw just 30,000 voters, party officials are going all-in to defend one of their top recruits and discredit O’Donnell.

“She’s not a viable candidate for any office in the state of Delaware,” said the state party chairman, Tom Ross, who is backing Castle. “She could not be elected dog catcher.”

State GOP officials have done everything in their power to take down O’Donnell. For example:

–After a conservative radio host took O’Donnell to task over incorrect claims she won two counties during her 2008 Senate bid against Biden — in fact, she won none of the state’s three counties — GOP officials gleefully shared the audio.

–When a New Jersey university last week finally awarded O’Donnell a degree she had claimed for 21 years, Republicans called it the latest example of her exaggerations.

–O’Donnell’s financial reports show donors are picking up her rent and utilities at a condo that doubles as a campaign headquarters. Republicans hasten to note O’Donnell’s dire personal finances that include threats of liens, foreclosures and an Internal Revenue Service audit. Republicans then questioned O’Donnell’s ability to handle tax dollars, and wondered about the marketing consultant’s reporting just $5,800 in income during a 15-month period.

–The Delaware Republican Party on Thursday filed a complaint with the Federal Election Commission accusing O’Donnell and the Tea Party Express of violating FEC rules that restrict coordination between candidates and outside political organizations. The complaint, filed for the party by campaign finance lawyer and former FEC chairman Michael Toner, states that the Tea Party Express solicited donors to contribute to O’Donnell and that O’Donnell and the group worked jointly on advertising, breaching agency rules.

“It is a shame the party is doing this,” O’Donnell said after a rollicking dusk rally across from the Delaware Capitol this past week. “Because I believe that we have the right principles to win this election.”

O’Donnell and her supporters just as eagerly point to Castle’s votes in support of the 2008 Wall Street bailouts, which were championed by Republican President George W. Bush, and Castle’s support for climate change legislation that has stalled in Congress. Those votes are immensely unpopular with conservative Republican voters.

“He’s getting harder and harder to support,” said Carl Williams, a retiree from Camden. “Castle should get off the Republican ticket. He says he’s a Republican, but he’s not a conservative.”

Others say Castle sides too often with Democrats; in a mailing, O’Donnell calls him “the most liberal Republican in Congress.”

“He’s gone too far left,” said Bob Haller, a retiree who carried a sign saying “Castle Voted Against God in Our Pledge of Allegiance.”

“He’s become nothing but a rubber stamp,” he said.

So in the nation’s first state, the contest has become a battle between a conservative activist’s fervent supporters versus Republican heavyweights. The race is shaping up to be a measure of the anti-establishment sentiment that views incumbency as a handicap and political inexperience as a valued quality.

The California-based Tea Party Express has pledged $250,000 to help bolster the cash-strapped O’Donnell. It’s not clear they will reach that goal; so far, officials have disclosed less than $150,000 in federal elections filings.

In campaign reports filed on Aug. 25, O’Donnell reported raising about $260,000 for her bid and had about $20,000 in the campaign bank account. Castle had raised $3.2 million and had $2.6 million cash on hand, which is why he has been able to spend freely on mail and television ads criticizing his rival.

The winner of the Republican nomination will face county executive Chris Coons. Unlike Republican-leaning Alaska, the Democratic nominee would have a better shot at the seat against O’Donnell, who lost to Biden 65-35 percent in 2008.

Hard feelings among Republican voters could linger well past Nov. 2.

“It angers me. I don’t think no Republican should really go after any Republican,” said Bill Valentine, who’s from Hockessin.

He’s not alone.

Sarah Palin, whose endorsements have proved beneficial to other conservative candidates, announced Thursday that she is backing O’Donnell, hoping again to thwart insiders’ calculations as she did in Alaska with Miller.

“She understands the politics of personal destruction,” O’Donnell said of Palin, “and I think that’s why she got involved.”

Republicans circulated audio of a testy, 22-minute interview that O’Donnell had with radio station WGMD on Thursday. Party officials also have said she inflated her resume and made flat-out untrue statements while being dogged by questions about tax liens and foreclosures. Castle says she has misrepresented his record.

“She’s not a viable candidate for any office in the state of Delaware,” state party chairman Tom Ross, who is backing Castle, said in a telephone interview. “She could not be elected dog catcher.”

Republicans said Castle’s campaign is preparing negative television ads against O’Donnell. The commercials would air in the week leading up to the primary. The campaign also has created a website, RealChristine.com, a clearinghouse of negative O’Donnell stories.

“Unfortunately, the truth always seems to be an issue,” said Ross. “Her version of reality doesn’t jibe with any of the facts.”

O’Donnell’s campaign did not return messages seeking comment.

The Tea Party Express has announced a six-figure commitment to back O’Donnell. A spokesman, Levi Russell, said the organization hopes to begin airing radio and television ads by the end of this week or early next week, and put the anticipated cost at about $250,000.

In the radio interview Thursday, O’Donnell refused to back down from claims that she won two of Delaware’s three counties in her 2008 Senate bid against Biden, despite numbers that show she didn’t.

“I was the 2008 endorsed candidate against Joe Biden and I won in two counties,” O’Donnell had told a group in Pennsylvania.

WGMD’s Dan Gaffney, a conservative radio host who backed O’Donnell’s Senate bid, asked her to explain the claim.

“Look at the results,” O’Donnell said. “What do they say? 49 (percent), 49. I call that a tie.”

She lost that county by 272 votes.

Commenting on Kent County, home to state capital Dover, O’Donnell said: “I said I nearly tied.”

The host played the audio again that shows she didn’t couch it that way. Flustered by the questioning, O’Donnell asked Gaffney whether he was being paid off by Castle, who has refused to debate her.

She then blamed her schedule for the missteps. “You’re on the campaign trail, starting at 5 a.m., you go to 12 … you go until midnight,” she said. “Sometimes you slip up on those things.”

Although private polling shows Castle with a comfortable lead, they want to avoid a surprise like Miller upending Murkowski.

Ross argued that the two candidates — O’Donnell and Miller — are far different.

“When you look at Joe Miller, he’s an Ivy League graduate, a war hero and an attorney who is prominent in the community,” he said. “We could go across the street from the apartment Christine O’Donnell rents and we probably couldn’t find anyone who knows her.”

Although O’Donnell has appeared on the ballot in the past, she faces an uphill race against Castle, Delaware’s sole representative in the U.S. House who won in 2008 with 61 percent of the vote.

Republicans also take some comfort in the calendar. The deadline to register in the Republican primary has passed; tea party activists energized by the upset in Alaska missed their chance to vote in the closed primary. The Republican winner will face Democrat Chris Coons.

And the past two days have brought two fresh reminders that more insurgents could still sneak through.

In Delaware, the news is that the Tea Party Express — whose $600,000 ad campaign helped key Joe Miller’s apparent upset of Sen. Lisa Murkowski in last week’s Alaska GOP primary — is set to launch a TV and radio campaign on behalf of little-known Christine O’Donnell, who is running against longtime Rep. Mike Castle in a September 14 Senate primary. To date, the contest has attracted scant media attention (and polling), and it’s been widelt assumed that Castle, who served eight years as governor before claiming the state’s lone House seat in 1992, would prevail with ease.

But as last week’s Alaska jolt demonstrated, it’s not always easy to see these Tea Party upsets coming, and in Delaware the rough formula exists: an establishment favorite — Castle is among the most moderate Republicans in the House — who currently holds statewide office facing a right-wing outsider with some impressive conservative credentials (and now, thanks to the Tea Party Express, with some valuable outside help). 

The small size of the GOP primary universe in Delaware could help O’Donnell, too, and if she does somehow win, it would severely complicate the GOP’s Senate math. It has been assumed all year that Castle would be the state’s next senator: The Democrats’ biggest name, Beau Biden, backed out, and polls have consistently shown Castle comfortably ahead of the Democrat who did run, Chris Coons.  But O’Donnell would be a different matter. The same Republican-friendly (this year, at least) independent voters who are so comfortable with Castle might think diffrently of an right-wing insurgent with impeaccable Tea Party credentials. Just as Angle’s extremism has given Harry Reid his only chance at surviving in Nevada, O’Donnell would present Democrats with their best — and probably only — bet in Delaware.

The rough formula also exists in New Hampshire, where on Sunday the state’s largest newspaper, the Union Leader, endorsed insurgent Ovide Lamontagne, one of four Republicans running in the September 14 primary for the seat now held by Judd Gregg. Lamontagne’s bid has seemed hopeless for months, with polls showing him running far behind state Attorney General Kelly Ayotte, the state and national GOP establishment’s preferred candidate.

But the Union Leader’s decision could provide Lamontagne with a spark. The fiercely conservative paper is unusually influential in right-wing circles and it tends to promote its chosen candidates more aggressively than other newspapers do. Plus, Lamontagne has been in this same position before. Back in 1996, he waged an insurgent bid for governor, running far to the right of Bill Zeliff, a moderate three-term congressman with strong establishment credentials. At this point in that campaign — three weeks before the primary — Zeliff led Lamontagne 46 to 19 percent. But as voters focused  on the race after Labor Day, Lamontagne surged, boosted by the Union Leader’s loud support (and its equally loud condemnations of Zeliff). In the primary, Lamontagne prevailed, 48 to 43 percent.

That example is instructive because of what happened in November. Running against a Republican nominee who could easily be caricatured as an extremist, Democrat Jeanne Shaheen positioned herself as a tax-phobic moderate and won over the state’s culturally moderate independent voters. She led wire to wire and posted a comfortable winning margin. Granted, the circumstances were ripe for a Democratic win in New Hampshire that year, with Bill Clinton cruising past Bob Dole by ten points at the top of the ticket. Shaheen may well have beaten Zeliff, too — but the task wouldn’t have been nearly as simple.

If Lamontagne were to knock off Ayotte on September 14, Democrats would have a similar opportunity. Polls have consistently shown Ayotte leading Rep. Paul Hodes, the presumptive Democratic nominee. With Ayotte as their candidate, the GOP is very likely to hold onto the seat, given the national climate. But a Hodes-Lamontagne race would be a far different proportion. Like Harry Reid in Nevada and Jack Conway in Kentucky, Hodes would have an opening to make the race, at least in part, a referendum on his opponent’s extremism. The culturally moderate independents who are ready to swing back to the GOP in New Hampshire this year might get cold feet. The national implications are serious for Republicans: A loss in New Hampshire, which would cost them a seat they already have, would make the math of a Senate takeover nearly prohibitive

To be sure, it’s possible the Union Leader’s decision won’t have much of an impact — that the gesture was mainly an obligatory one and that fomenting a conservative backlash against Ayotte will be far more difficult than it was with Zeliff. For all of the paper’s success in shaping GOP primaries, it has has some real clunkers too, like its 1988 endorsement of Pierre S. duPont IV for president. Ayotte may still win easily on September 14.

Similarly, O’Donnell’s camapign against Castle may end up going nowhere. Not every moderate, establishment-backed Republican has faced primary drama this year: Mark Kirk in Illinois, for instance, had no trouble securing the GOP nod back in March. But in the wake of Miller’s out-of-nowhere (apparent) triumph, Delaware and New Hampshire are worth watching a little more closely these next few weeks.