In news reports about his tax problems, former Sen. Tom Daschle seemed far removed from his Midwestern roots. Long gone was the young Democratic representative from South Dakota whose TV ads once touted that he still drove his dusty old car around the nation's capital. Instead, Daschle, President Obama's pick to lead the Department of Health and Human Services, came across as the consummate Washington insider -- a jet-setting consultant who hadn't paid $128,000 in taxes on the chauffeured limousine service provided by a wealthy private-equity investor.

But the stand-up South Dakota guy in Daschle reemerged Tuesday as he withdrew his nomination as HHS secretary. That position, which would have made him the architect of the looming overhaul of the American health-care system, surely was the long-sought pinnacle of a distinguished career in public service. But it is also a position requiring the full confidence of the American public, of the health-care industry and of congressional leaders.

Everyone will be deeply and personally affected by the coming health-care changes. Especially at this historic moment, there cannot be one shred of doubt about the credibility or motivations of those shaping that policy. Daschle's insistence that he didn't realize he had to pay taxes on the limo service rang false; as the former Senate majority leader, he helped shape the nation's tax code. The tax issue and the potential conflicts raised by Daschle's speaking fees from the health-care industry would have jeopardized his ability to make the massive changes so sorely needed. Stepping aside was the right thing to do.

While it will be challenging to find a replacement with Daschle's expertise in health and politics, it's not impossible. President Obama has a Democratic majority in Congress and was swept into office with a mandate. Daschle's muscle in moving a health-care overhaul through Congress would have been useful, but it was not the key to reform. The critical component remains an intelligent, carefully crafted plan -- one that will win support on its merits.

Two weeks into office, Obama has some explaining to do. On Monday night, comedian Jay Leno joked about finding anyone in the Obama administration who had paid their taxes in full. It was a joke, but it's a question that needs to be taken seriously. There's a troubling pattern emerging with the president's Cabinet picks. Daschle's decision came hours after Nancy Killefer, nominated to be the nation's first federal performance officer, withdrew because she hadn't paid some payroll taxes for household help. Timothy Geithner, the recently confirmed treasury secretary, hadn't paid $34,000 in self-employment taxes. Bill Richardson, the governor of New Mexico and nominee for commerce secretary, also withdrew under a cloud. Federal investigators are looking at transportation contracts landed by his political donors.

This batch of troubled nominees raises a number of questions. Is the federal tax code so impenetrable that no one can be absolutely certain they've complied with the law? Simplifying the tax code is long overdue. Still, it's no excuse for the Obama transition team's poor performance in vetting Cabinet nominees. Supposedly the best and the brightest, they failed to do due diligence, leaving a young president who campaigned under the banner of reform looking like he's engaged in politics as usual in Washington. Obama came into the office with an extraordinary amount of goodwill. He shouldn't have to spend so much of it so quickly on Cabinet nominees.