It's been a good couple of weeks for the presumed presidential aspirations of Minnesota Gov. Tim Pawlenty.

But it's been rough going for Pawlenty's party -- and thus for the country -- as America is best served by a robust opposition party with many strong candidates.

Two potential Republican presidential candidates, South Carolina Gov. Mark Sanford and Alaska Gov. Sarah Palin, made abrupt announcements, with serious political and personal ramifications. Sanford, whose Appalachian-turned-Argentinian adventure might derail his marriage and his presidential ambitions, may yet heed the call of many within his own party to resign.

Palin actually did quit in a surprise move that will do little to convince her critics that she has the governing gravitas needed for a presidental run. Indeed, after becoming an overnight political (and pop culture) sensation with her vice presidential nomination acceptance speech at the Republican National Convention in St. Paul, her unscripted moments showed her more wobbly than wonky on the intricacies of international and national affairs. Many expected her to return to Alaska, hit the briefing books and use as tutors the many bright minds in her party who recognize her natural political and communication capabilities.

Instead, she seemed to spend most of her time in conflict, including with David Letterman and legislators -- many from her own party. Republican Lyda Green, a former president of the Alaska Senate, told the New York Times that "the longer she stays in, the more people become disenchanted and see something they haven't seen before. This has been a pretty precipitous fall."

Historically, Republicans have rightly looked at states as living laboratories of policy innovation. But beyond policy, effectively and efficiently running a state is good politics -- the kind that can augment arguments that bloated Beltway programs are too expensive and inflexible. Palin could have bolstered her state and her political résumé by finishing her term and focusing on alternative models of government that might offer a new route not just for the country, but for California, New York, Minnesota and every other state struggling with perplexing budget issues and, as Palin might put it, cultures of "politics as usual."

And beyond the dire domestic issues brought on by falling revenues and rising costs, any presidential candidate needs to cross a credibility threshold in international relations. If she's serious about a 2012 presidential bid, Palin now faces that challenge without the benefit of holding public office.

How the GOP presidential lineup will shake out remains to be seen. There will be other formidable candidates, including former Massachusetts Gov. Mitt Romney. And Sanford's contrition tour and Palin's vow to "fight for all our children's future from outside the governor's office" may yet work.

Meanwhile, the Minnesota governor methodically and strategically presses on, even after a politically polarizing legislative session. While his potential opponents were making headlines that had pundits handicapping whether they have political futures, Pawlenty was headlining a political fundraiser in Arkansas.

You can bet Pawlenty will finish his term and continue to avoid the kind of drama surrounding Sanford and Palin. That stability alone, in an unstable world, is an essential element for any leader, especially one who may aspire to lead the country.