There is increased pressure on Barack Obama to cut ties with long-time Democratic insider Jim Johnson, who Obama had tapped to help select his running mate.

Johnson stands of accused of, among other things, getting a seven million dollar below-market rate home loan from Countrywide Financial through an informal program set up for friends of the embattled mortgage company's CEO.

Obama has, in the past, used strong language in railing against Countrywide and other subprime lenders, making his association with Johnson--and Johnson's with the lender--awkward.

So far, Obama has yet to dismiss Johnson with his trademark "this is not the Jim Johnson I know" kiss off. But a controversy surrounding the "vetting of a vetter" is an ominous sign for what is about to become a brutal political slog.

During the Clinton/Obama primary fight, a favored tactic of both sides was to hit at the other through the gaffes and biographical glitches of their surrogates and associates, and then to suggest their opponent distance themselves from said surrogate or associate. What prevented this from getting completely out of hand was that every couple weeks there was something more important to focus on: actual voting results.

Only now, since there won't be any of that voting stuff until November, there will be plenty of time to play the guilt-by-association game to its under-the-bus-tossing end. The revelations about Johnson are surely the tit for a tat the Obama camp launched a couple weeks ago when they put pressure on John McCain to get rid of advisers who had done work as lobbyists.

But, cynical political maneuvering aside, is it even wise for the McCain camp to force Obama to get rid of Johnson? Maybe not. Twice before, Johnson has vetted VPs for the Dems. First, in 1984, he came up with Geraldine Ferraro, but neglected to uncover that the New York congresswoman's husband's finances were a criminal mess. Then, in 2004, Johnson suggested John Edwards, who never jelled with John Kerry, and who was only able to increase the Democrats vote share in his home state of North Carolina by .4 percent.

Whether it be Jim Johnson or John Hagee, could there be wisdom in letting the other guy's liability stick around long enough to do some real damage?

For more by Jeremy Taylor: http://www.jeremysspecialblog.blogspot.com/