Looking at the Gallup Daily Tracking Polls every day, as some of us do, we see two sets of numbers -- Clinton vs. Obama among Dems, and McCain vs. both Dems among all voters. The prior is volatile and unpredictable; the latter is so steady, it's hardly worth watching.

Take a look at today's report, for example. Over the past few weeks, Obama's lead was huge, then small, then gone, then big again -- but all the while, in a general election matchup, he and McCain are just about tied at 45 percent each. The same goes for a matchup pitting Clinton against McCain. No matter what's going on in the news, or what the controversy of the day is, those general election polls just don't budge.

So, is this encouraging or discouraging? I posed the question last week, noting that there's two entirely opposite but completely reasonable interpretations here. One is that Dems are lucky to still be tied with McCain, given that he's had it easy while Clinton and Obama have been tearing each other to shreds. The other is that Dems should be crushing McCain, given that he's running on a Bush-like platform and Americans are thoroughly unhappy with the status quo.

Jonathan Cohn argues today that McCain's 45 percent standing against Obama or Hillary "represents a ceiling of his support."

After all, barring some outside shock to the political system, there is no reason to think McCain's numbers will go up. People already have overwhelmingly positive feelings about him -- stronger than about either of the Democratic candidates. They see him as a likeable, principled war hero whom they trust on national security. Very few realize that he has supported privatizing Social Security, that he opposes universal health insurance, that he supports free trade without qualification, and so on. Once the voters learn these things, at least some of them are likely to abandon him.

If anything, McCain has the look of an Internet stock circa 1999: Great numbers, lousy fundamentals.

That's relatively persuasive, but is it a good reason to let the Democratic race continue?

If Democrats are poised to do very well "once the voters learn" about McCain, it may very well be time to start informing them. After all, Dems have a very powerful case to make against McCain, but they can't make it while the party is divided in half and they're waiting until late August for a nominee.

McCain has high favorability ratings, nearly universal name I.D. and the enduring love of every major news outlet in the country. The sooner Democrats start making their case against McCain -- which really isn't that tough to make -- they can position themselves for an incredibly successful, possibly even historic, year -- at the top of the ballot on down.

The chances of this happening in a truncated, eight-week general election campaign, with a divided Democratic Party and a Republican nominee who will have a five-month head start, are considerably smaller.