Sarah Palin has played politics consistently, if not always with consistent success, during the 2010 Republican primary season. But in her home state of Alaska, she appears to have engineered one of he most remarkable political upsets of an already volatile year.

Palin provided the publicity, fundraising umph and political push for a challenge by newcomer Joe Miller’s audacious challenge to incumbent Republican Senator Lisa Murkowski.

Palin’s had a running feud with the Murkowski family for years. She beat Lisa’s dad, Frank, in the 2006 GOP gubernatorial primary that put the former mayor of Wasilla on the fast track to the 2008 Republican vice presidential nomination. And there was even talk this year that Palin might challenge Lisa Murkowski, who was appointed to the seat by her dad.

Palin was not about to lower her own sights to the Senate level. But she worked hard for Miller, a previously unknown candidate who was challenging the biggest name (aside from Palin) in Alaskan Republican politics.It wasn’t an ideological fight; Lisa Murkowski has served, by most measures, as a conservative. It was personal.

And Palin went to the mat for Miller, finishing off the primary race by recording a robocall for the challenger in which she identified herself as "Governor Sarah Palin"—conveniently dismissing the fact that she quit the state’s top job more than a year ago.

Palin’s push gave Miller an apparent win, with incomplete results placing him more than 5,000 votes ahead of the incumbent Wednesday morning.

In fairness, this was just one race in one state—a state where Palin has been a player longer than anywhere else.

Still, this is the upset of the year so far. And Palin was at the center of it. Miller, an attorney from Fairbanks who got in the race late and with little money, did not hesitate to credit Palin, saying of the former governor’s support: "I’m absolutely certain that was pivotal."

Murkowski seemed to feel the same way. She ripped into Palin on primary day, saying: "I think she’s out for her own self-interest. I don’t think she’s out for Alaska’s interest."

Murkowski may be right.

But if Palin played in the Alaskan Senate race with an eye toward advancing her own self-interest, it worked.

The GOP’s former vice presidential candidate’s star, which was already showing, is going to shine a good deal more brightly. And her favored candidates, not just in Alaska but around the country, are going to be more determined than ever to get her campaigning on their behalf.

This is something that Democrats, if they are smart, need to figure into their calculus.

Palin is a complex and volatile figure; indeed, as the Murkowski result indicates, she can be as much trouble for mainstream Republicans as Democrats. But she is the hottest political property of the moment, a far more significant player than she was at the start of the 2010 electoral cycle. Her determination to engage, often (though not always) in opposition to the GOP establishment, suggests that—with the probably if not certain exception of President Obama—she will be the highest-profile figure on a fall campaign trail that she intends to work aggressively.

It may be true that Palin is weak when it comes to policy details. It may be true that she plays loose with the facts. But she is strong when it comes to campaigning and the fact is that she is willing to take risks that most politicians avoid. As such, she’s going to be a force to be reckoned with this fall, bringing political star power not just to the usual Republican suspects but to a lot of candidates who—like Alaska’s Joe Miller—had been counted out by poltical insiders. Democrats ought not fool themselves about the Palin factor. Indeed, if they underestimate this emerging reality, they will do so at their political peril.