In the past 30 years or so, since presidential conventions no longer actually have decided the nominees, their usual purpose has been to focus and project a positive image of the already chosen candidate (and, of course, disparage the opponent). But last week in St. Paul, Minn., the GOP convention was different. It not only enhanced but also -- at least for the moment -- reversed-fielded the image of the Republican ticket.

In the aftermath of that reversal, the entire presidential contest has been upended. It also hastened (or perhaps even made possible at all) the change of the human image of the GOP from Bush/Cheney to McCain/Palin.

Until last week, Sen. McCain was running as the boring candidate of experience and was unable to substantially replace Bush as the image of the party. With Bush having a 70 percent negative image, he not only was dragging down McCain but also constituted a drowning weight on the buoyancy of Republican candidates at the federal, state and local levels.

But with the addition of Alaska Gov. Sarah Palin to the ticket, suddenly and spontaneously, McCain the reformer, McCain the maverick stopped being a GOP talking point and became incarnate. It is not only that the Alaska governor is a genuine reformer but also that by every aspect of her being, she is fresh, different, recognizably normal, and thus, the un-Washingtonian. The power of her image has supercharged McCain's image.

We see the first effects of McCain/Palin replacing Bush/Cheney in Monday's USA Today/Gallup Poll, in which 48 percent say they're Democrats or lean to the Democratic Party; 47 percent say they're Republicans or lean to the GOP. That merely 1-point party gap -- the strongest position for Republicans since Bush's second inaugural, at the beginning of 2005 -- had been in double digits only a few weeks ago. Moreover, voters -- by only 48-45 percent -- support the Democratic candidate in their congressional districts, the Democratic Party's narrowest advantage this year. If these numbers hold -- and it is a big if -- Republicans may well lose far fewer seats in the House and Senate in November.

Moreover, in an act of political alchemy, McCain's selection of the nationally inexperienced Gov. Palin only underscored Sen. Obama's own national inexperience. Worse for Obama, Gov. Palin's presence has sucked the oxygen out of Sen. Biden's public statements -- forcing presidential candidate Obama into the unthinkable: He himself must go on the attack against McCain's vice presidential junior partner. Worst of all for Obama, his campaign of a fresh face with new ideas is falling victim to a newer face with newer ideas.

As I predicted in a Feb. 28, 2007, column:

"What does it mean to be a 'fresh face' in a 12-month primary campaign in an Interneted, 24-7 news cycle environment? This, of course, must be a question that Sen. Barack Obama and his people are puzzling over now. He will be as familiar as an old shoe to Democratic Party primary voters by next January (2008) and February (2008). He may still be appealing next year (2008), but he will no longer be fresh.

" A new idea put forward a year before primary voting risks not only providing more than sufficient time for an opponent's research team to find and publicize the flaws in the idea but also runs the risk of becoming stale and, most dangerously, of letting events overtake the proposal.

"Thus is lost one of the great advantages of challengers -- that their ideas are fresh, appealing and plausible, but not public long enough to be measured by events and considered judgment -- which is the inevitable plight of incumbents and their party successors.

"One of the other imponderable challenges to both fresh faces and well-known veteran candidates is how to manage the life expectancy of clever phrases and slogans and even of endearing personality quirks and styles of speech or manner.

"These things tend to get old.

"I suspect that the insatiable public maw of freshness-hunger will prove a vast challenge to the wordsmith and media shops of all the campaigns.

"Perhaps this will be the election cycle of the late entries."

And that is exactly what Obama is being forced to deal with. First his startling and lofty rhetoric grew stale from overuse. And now his once engaging (for some) ideas are being overtaken by events. His call for quick retreat from Iraq, overtaken by the surge and the smell of victory, has forced him to reverse field and admit the surge has been an unexpected (by him) success. Then the declining economy forced him this week to back away from his soak-the-rich tax increases for fear of further damaging the economy.

Of course, the perils of Pauline still may threaten Gov. Palin, and two months is time enough for many more strange twists. But one week on from the Republican convention, it is fair to say that never in modern history has a presidential ticket benefited so much from its convention. And never have the hopes and energy of a moribund party risen so quickly or so high.