Just when you thought the Republican presidential field was getting set, up pops the most mischievous force in American politics, Sarah Palin. The former Alaska governor — the real deal this time, not actress Julianne Moore channeling her for the filming in Maryland of the movie "Game Change" — dropped by Fort McHenry on Monday in a non-campaign stop in her non-campaign bus on her (wink wink) non-campaign tour of the East Coast, which ends, in what must be pure coincidence, in the first primary state, New Hampshire.

While in Baltimore, according to a Los Angeles Times reporter who was able to keep up despite the lack of a public schedule, Ms. Palin read a manuscript of the "Star Spangled Banner;" hoisted a 36-pound cannon ball; briefly upbraided President Barack Obama for referring to the U.S. military during a Memorial Day observance as "one of the finest fighting forces in the world," as opposed to the finest; and in a particularly mavericky touch, paid a compliment to another noncandidate, Gov. Rick Perry of Texas.

All this action from the Fox News commentator, plus her recent purchase of a home in Arizona, which could be a perch in the Lower 48 from which to launch a presidential run, has delighted all ends of the political spectrum. In fact, it's hard to tell who's more excited, Ms. Palin's many fans or the Democrats who think she'd be easy to beat.

But even before Ms. Palin's re-emergence on the national stage, Democrats seemed to be feeling pretty confident about the caliber of the Republican field. Once Govs. Mitch Daniels of Indiana and Haley Barbour of Mississippi, former Arkansas Gov. Mike Huckabee and (let us not forget) Donald Trump announced they wouldn't run, the GOP appeared to be left with contenders or potential candidates who were all flawed or unable to unite the party's traditional constituencies.

Former Massachusetts Gov. Mitt Romney is Mormon (which turns off some evangelical Christians) and has the distinction of having enacted a universal health care plan in the Bay State that looks an awful lot like Obamacare.

Rep. Ron Paul has a dedicated following, but his strict libertarianism (he favors, for example, legalizing heroin) takes him places many voters don't want to go.

Former House Speaker Newt Gingrich has a tendency to say things he regrets (witness his criticism on "Meet the Press" of the Republican House budget plan, and then his backtracking shortly thereafter). Plus, there are the three wives, the affair with the third while he was pursuing impeachment of President Bill Clinton, and, most recently, the $250,000-$500,000 charge account at Tiffany.

Former Godfather's Pizza CEO Herman Cain has been attracting tea party support, but he is a virtual unknown on the national stage and has never held public office.

Rep. Michele Bachman, another tea party favorite, managed to annoy the GOP establishment by giving a rogue tea party response to the State of the Union address — and whiffed the opportunity besides by staring into the wrong camera.

Former Utah Gov. Jon Huntsman, who has recently been exploring a campaign, favored civil unions for gays and, perhaps worse from a Republican perspective, served as President Obama's ambassador to China.

With that field, some wise heads have recently been predicting that the party would begin to unite behind former Minnesota Gov. Tim Pawlenty, who has no obvious flaws other than the fact that he's been polling somewhere in the vicinity of dead last.

But Democrats shouldn't get too excited, and Republicans can stop speed-dialing former Florida Gov. Jeb Bush or any of the other imagined saviors of the 2012 election. We're at the phase of an election in which it's easy to see all the reasons why someone can't possibly win but very difficult to see the reasons why they could. Twenty years ago, the Republican president was riding high in the polls after the first Persian Gulf War, and the Democrats were assembling their own field of flawed candidates, and none more flawed than a draft-dodging, pot-smoking (though not-inhaling), womanizing governor of a small Southern state. That turned out a bit better for the Democrats than they might have expected.

The Republicans have always been the party in which the establishment rallied behind a chosen candidate, and its understandable that some might be nervous that it isn't turning out that way this time. But it's time to stop fretting about who's in and who's out and to start listening to what these candidates have to say about where they would lead this country.

It's rare that we agree with something Ms. Palin says, but she had it absolutely right when she noted at Fort McHenry, "Competition breeds success. I would hope there is gonna be vigorous debate and a lot of aggressive competition even in our primary so that our voters have a good choice." We couldn't have said it better ourselves.