Iowa performed its quadrennial service to the nation, and for that we should be thankful. For all the complaints about the state's caucus system, Iowans' demand that candidates show up in person, at small venues, is a solid test of a campaign's strength. Donald Trump, who thought he could get by on mass media and a few big rallies, got schooled on that. Ted Cruz, who outperformed nearly every poll leading up to the caucus, demonstrated a mastery of how to turn out his supporters that makes him a serious contender.

New Hampshire will perform a different service next Tuesday. The flinty voters of that state are far less susceptible to the preacher rhythms beloved by evangelicals and will be waiting to hear GOP ideas on the fiscal issues they hold dear. It's past time for that, and they should press candidates for more than the sound bites that have dominated to this point. In particular, voters should seek answers from those who would repeal the Affordable Care Act on what their replacement would be. A return to previous high numbers of uninsured and coverage being refused for preexisting conditions is not acceptable. The pace will only quicken after New Hampshire, so the time for a close examination of candidates' proposals is growing short.

The big personalities and high drama among this year's candidates have resulted in record ratings and engaged voters. It's been fun and is far preferable to the apathy of some past elections, but there is work to be done by voters before some of the most experienced candidates are forced out, leaving mostly the untested.

Minnesota's turn is coming soon. On the GOP side, a winner-take-all format heightens the responsibilities of caucusgoers to ensure the state's delegates are awarded to a serious candidate with sound ideas. Marco Rubio, who surged to a strong third-place in Iowa, and who did well in a recent Star Tribune Minnesota Poll, could find fertile ground here if he brings substance as well as show.

Hillary Clinton eked out a win over Bernie Sanders, but revealed an enormous "youth gap" that she must close to remain viable, particularly if Republicans choose a candidate who can energize young GOP voters. Declaring victory last night while the Iowa race was too close to call was poor form on Clinton's part and could create lasting enmity among those whom she can ill afford to have stay home if she's the nominee.

Sanders' appeal to progressive elements of the party is unquestionable, but Democrats will have to ask themselves some hard questions about which candidate could work productively with what may well be another GOP-dominated Congress that would be deeply skeptical of any new spending or increased taxes.

Republicans have a deep yearning, evidenced throughout this race, for a non-establishment candidate. Well and good. The republic needs those from time to time. But they also are badly in need of a candidate who can rebuild a vibrant, ideas-based GOP that goes beyond fear-mongering and cheap rhetoric.