Is there anything more thrilling than a war of memos from strategists for the two Democratic rivals, arguing over which candidate is more likely to win in a general election? (Don't answer that.) Last week, Barack Obama's staff came out with a memo explaining why their horse was the right one to back; this week it's Hillary Clinton's staff's turn. Obama's campaign relied on recent polling for its arguments, while the Clinton memo, authored by chief strategist Mark Penn, anticipates Republican arguments to come and explains why Clinton can refute them.

The full Penn memo, titled "Why Hillary, Not Sen. Obama, Is the Democrat to Beat McCain," is after the fold.

"During this campaign, one of the key arguments for Hillary's candidacy is that she's tested, vetted and ready to lead on day one. How does this factor into voters' decisions now that it appears John McCain will be the Republican nominee? Let's envision how a general election between the Democratic nominee and John McCain will unfold, based on recent elections:

"The GOP Attack Machine Will Redefine the Democratic Candidate; Hillary Has Withstood That Process. As soon as the Democratic nominee is selected, the entire force of the GOP attack machine will bear down on that nominee. This attack machine has been built and honed over decades; it is formidable, and employs all forms of media, from talk radio to major newspaper columns to television, email, blogs, websites, direct mail, and extensive ground networks. It was able to skew public perceptions of two well-respected Democrats, Al Gore and John Kerry, creating impressions about them that were wildly out of step with reality. Hillary Clinton has withstood the full brunt of that machine and actually emerged stronger.

"Sen. McCain Will Run on National Security; Hillary Wins That Argument. When it came to national security, "strong and wrong" won out over "right and weak" in the 2002 and 2004 elections. With Hillary, that is not and will not be an issue: Based on what they know of her and her experience, voters believe Hillary is fully ready to be commander in chief. She will be strong and right. Voters know she has the right policies -- ending the war in Iraq, re-establishing our relations with our allies -- and they know she has the strength of leadership that America's next president will need in a world that can turn dangerous in an instant. As such, the Republicans will not be able to play the national security card against Hillary Clinton, like they are now doing against Senator Obama, and that makes her a fundamentally stronger candidate against John McCain. Case in point is what George Bush said on Sunday morning about Sen. Obama, 'I certainly don't know what he believes in. The only foreign policy thing I remember he said was he's going to attack Pakistan and embrace Ahmadinejad.' With Hillary, the Republicans' national security argument blunted and the election debate will shift to healthcare and the economy -- areas of decisive strength for Hillary.

"Sen. Obama's Negatives Will Rise; Hillary's Are Already Factored In. Sen. Obama himself has been saying that even after a year, voters in places like Texas and Florida don't really know him that well. So how much do independent voters know about Barack Obama, his voting record and his past positions? Even less than Democrats know. For example, he recently told voters in Idaho that he favors the Second Amendment -- but he didn't mention that, in the past, he supported a complete ban on all handguns. If he were the nominee, the Republican attack machine would have immediately rolled out his full record -- and his independent Idaho support would have evaporated. So far, the Republicans have been laying low. Sen. Obama has never faced a credible Republican opponent or the Republican attack machine, so voters are taking a chance that his current poll numbers will hold up after the Republicans get going. With Hillary, the GOP has already tried just about every attack and has failed. Those attacks are already factored in her ratings, where she remains competitive against Sen. McCain. But when it comes to Sen. Obama this is a big unknown, and the likelihood is that his negatives will rise.

"The Resiliency of Sen. Obama's Coalition Will Be Tested; Hillary's Coalition Is Stronger. The grind of a general election will erase the freshness and excitement of the primary season and the success that Sen. Obama has earned in states he has little chance of winning in November will erode. It may even crumble. Sen. Obama will have to fall back on core Democratic voters to stay competitive with McCain. But this is where Hillary has already built a powerful base, with overwhelming support among women, Latino voters, and other stalwarts of the Democratic Party. Hillary's coalition, which has carried her to victory across the country, is a winning coalition against Sen. McCain since it draws from the voters Sen. McCain will need to win. Look no further than Super Tuesday for proof: Hillary won by double digits in the big states that any Democrat must win to defeat John McCain. And in Missouri, Hillary won all the swing areas, getting 110 of 115 counties.

"Current Poll Numbers Don't Tell the Story of What Will Happen: Sen. Obama Routinely Underperforms While Hillary Overperforms. After winning the Democratic nomination in 2004, John Kerry vaulted to a 17 point lead over George Bush. Even on Election Day, virtually every pollster said John Kerry would win. It did not happen. Today, commentators are touting a Time poll that shows Sen. Obama faring slightly better than Hillary Clinton against John McCain. Last week, the pundits were using a handful of polls to argue that Hillary Clinton would lose NJ, CA and MA. None of that happened. Instead, Hillary Clinton has repeatedly confounded pollsters and the chattering class by doing better on Election Day than the polls suggested she would -- in NH, MA, NY, NJ, CA, and AZ. Her 2000 election was no different -- exit polls suggested she might lose a close race but she ended up winning a landslide victory when the actual votes were counted.

"Hillary is the best candidate to take on Sen. McCain and defeat him. She has outperformed at the ballot box throughout her career. She will neutralize the argument on national security so the election will turn on her ability to manage our economy and reform healthcare. The GOP will not be able to increase her negatives in a way they can with an untested candidate. And Hillary's core voters -- working class, women, Latinos, Catholics -- are exactly the voters that comprise the key swing voters the party has needed in the past to win. This is an observation I made in the Washington Post after the 2004 election, 'Middle-aged women and Hispanic voters were key voting blocs that made the difference, swinging the vote from Kerry to Bush. In fact, in 2004 women made up 54 percent of the U.S. electorate, the highest percentage in history. Their interest in and impact on politics has been increasing.'"