Sensing blood, the McCain campaign wasted no time in attacking the Obama campaign for reversing course on a controversial adviser. Earlier this afternoon, the Obama campaign announced Jim Johnson, a former Fannie Mae CEO and head of Obama’s vice presidential nominee vetting team, had resigned after coming under fire for receiving several favorable loans. The McCain campaign quickly released a statement:

“Jim Johnson’s resignation raises serious questions about Barack Obama’s judgment. Selecting the vice presidential nominee is the most important decision a presidential candidate can make and one even Barack Obama has said will ’signal how I want to operate my presidency.’ By entrusting this process to a man who has now been forced to step down because of questionable loans, the American people have reason to question the judgment of a candidate who has shown he will only make the right call when under pressure from the news media. America can’t afford a president who flip-flops on key questions in the course of 24 hours. That’s not change we can believe in.” –McCain spokesman Tucker Bounds

On the McCain camp’s McCain Report blog, Mark Goldfarb also tore into Obama’s decision:

[T]he Obama campaign has shown remarkable dexterity in moving from the "overblown and irrelevant" message on Monday, to a "game" over someone who is only "tangentially related" to the campaign on Tuesday, to "you’re fired" on Wednesday. It’s the kind of change that looks very familiar to anyone who’s ever picked up the Washington Post.

Today’s developments come with the McCain campaign still smarting from last month’s loss of several advisers to new rules for lobbyists working on the campaign following attacks from Obama and the Democrats. Goldfarb, in the same post, has already indicated that the sights have now been set on another member of Obama’s VP squad, Eric Holder.

Finally, we presume that the new head of Obama’s VP search team is Eric Holder, who is described today by National Public Radio as having "played a role in helping fugitive financier Marc Rich get an 11th hour pardon from President Clinton."

With the nasty part of the campaign season in full swing, chances are we can look forward to many more of these accusations, then denials or claims of irrelevance, eventually culminating in resignation. It will be interesting to see how many advisers make it through to November with their skeletons safely in their closets.