ST. PAUL – Alaska Governor Sarah Palin will on Wednesday night deliver the most anticipated address to a national party convention in decades.

And Mary Buestrin can’t wait.

“Our people are pumped,” says the Republican National Committeewoman from Wisconsin, the state that former White House political czar Karl Rove this week described to delegates as the most evenly divided along lines of red and blue in the country. “This is Sarah Palin’s introduction to America. If she gets it right, and I think she will, her speech will give Republicans the boost we need to win this election. This is such a big deal”

Buestin is right about Palin’s speech being a big deal.

In America’s rigidly choreographed politics, it is rare indeed that an individual leaps from obscurity to a primetime speaking slot at a national political party convention. And it is rarer still that the individual is put in a position to make or break a presidential campaign.

But that’s the position into which Palin, who most Americans had not heard of a week ago, and whose name is still being mispronounced by top McCain aides, has been thrust.

Never before has the address of a vice-presidential pick mattered so much – not merely to the party faithful who will enthusiastically nominate a governor who speaks their social-conservative language but to the broader contest that will begin Friday morning.

If Palin delivers a brilliant speech, the sort that electrifies the convention and draws praise even from cynical pundits, she will be the fresh face of a Republican party that, after eight years of George Bush, Dick Cheney and Tom DeLay, needs nothing so much as an image makeover.

If the governor stumbles, even if she simply gives an O.K. address to delegates who do their best to cheer her on, Palin will open up a long and potentially disqualifying discussion about the judgment of the man who selected her as his running-mate: presumptive Republican presidential nominee John McCain.

McCain’s selection of Palin has electrified grassroots Republicans, especially social conservatives who share the hard-line anti-abortion rights, anti-gay rights, anti-stem cell research, anti-immigration stances taken by their presumptive vice-presidential nominee. Party activists who were skeptical about McCain – a man whose deviations from Republican orthodoxy had inspired distrust and disenchantment among the faithful — are flooding party phone-banks with offers to volunteer for the campaign, giving money at unprecedented rates, showing up at rallies in numbers that rival those of events for Democratic nominees Barack Obama and Joe Biden, and generally breathing life into a Grand Old Party that until last week was looking old and bitter.

Mary Verich, a Republican volunteer sporting a big “I Vote Pro-Life” pin, bluntly declared that Palin had renewed her party.

“I’ll be honest with you: I wasn’t energized until he picked her,” said Verich. “Now, I’m ready to get out and work for the ticket. That’s how important she is.”

Statements like that of Verich are typical on the floor of the Xcel Center where, in almost every sense, this has become Sarah Palin’s convention – not John McCain’s.

Don’t get these Republicans wrong. They were going to try and elect McCain, if only because to prevent Barack Obama from occupying the Oval Office. But McCain, whose maverick” reputation was earned by breaking with GOP orthodoxy on issues ranging from immigration to gay rights to taxes, was never a favorite of the faithful.

Palin closed the enthusiasm gap.

“We needed a push. And, oh my gosh, did we ever get it,” says Buestrin, a key player in national Republican politics for many years, who huddled with Rove Tuesday morning to discuss electoral strategies for fall contests in Midwestern battleground states that she now thinks are “winnable.”

“It’s mind-boggling what Sarah Palin has done for the party,” says the woman who was in charge of the logistics for this year’s convention. “Now, she just has to give a great speech.”

Will Palin do it?

Alaskan delegates were confident.

“She’s actually a great public speaker, and she’s a great debater – Joe Biden should be scared,” says Pat Fink, a delegate from Fairbanks. “I don’t know who all will contribute to it, who all the speechwriters will be. But I know she will deliver it well. She always does.”

Gene Brokaw, a delegate from Anchorage, who like Fink was wearing a white hard hat with a map of Alaska and the words “Drill Here!” printed on it, chimed in. “The country doesn’t know Sarah Palin yet. But they will after tonight. Sarah Palin’s going to be star of this convention.”

That’s no understatement. Palin is already the rock star of this convention — at least for the delegates, alternates and acolytes gathered inside the hall. And, beyond the hall, she is the only story of this convention.

For the first time in history, the biggest speech of a national party conclave is not coming on the last night when the presidential candidate takes the podium.

It is coming on the night when the vice-presidential candidate, a woman far more in tune with the party base than the presidential nominee, will speak to her frenzied followers and to a nation that tonight begins the process of deciding whether it wants to place the favorite contender of the most conservative Republicans ever to gather in convention one heartbeat away from the presidency.