In first half of the SC Congressional Black Caucus debate, listeners saw both a sharp exchange over substantive issues (health care plans, sub-prime lending, usury, etc), and a series of sharp swords over character issues. The interests of the Democratic party and the longer-term interest of its candidates were best served by the debate over substantive issues.
For months, it has been apparent that many Obama supporters seem to think a focus on character issues is a winning strategy for the nomination. This is, in my opinion, naive. First, it is a bit early to say who will benefit or lose the most from the exchange. Second, there are risks of turning up the heat in this area. No one is purer than the driven snow.
Big elections are won by candidates who are judged by voters to be basically honest and trustworthy, but rarely (never) by candidates judged to be perfect. There need to be standards. Campaign opponents, the press, bloggers and others will always get around to character issues. Every candidate will get worked over pretty good, before a vote in November.
Doing some due diligence now is prudent. But what is not prudent is making this the main focus on the campaigns. In the end, voters are sophisticated and cynical enough to recognize that politics is a rough game, and they will pick the flawed (but acceptable) candidate who will make them better off.