(Washington) Presidential candidates Barack Obama and John McCain are criticizing each other in new television ads, trying to drive down public opinion of one another with six weeks left in the election.

In his ad, McCain portrays Obama as a product of corrupt Chicago machine politics. Obama says in his spot that McCain’s proposal to deregulate health care could have disastrous effects like the deregulation of Wall Street.

The commercials come as the two candidates are locked in a tight race leading into their debates and then the final campaign push. Both campaigns say they are airing as part of national buys, meaning they aren’t targeted to battleground states and are probably meant to drive negative news coverage of each other as much as reach key voters directly on television.

The Obama spot shows photos of McCain with President Bush and quotes an article written by McCain in Contingencies Magazine that argues for more deregulation of the health care industry just “as we have done over the last decade in banking.”

“Increasing costs and threatening coverage, a prescription for disaster,” the ad says over video of a somber couple examining their bills. The McCain campaign says Obama is making an “absurd” argument because McCain wants to allow Americans the ability to buy health care across state lines in the spirit that allows Americans to do interstate banking - which isn’t the problem that caused the crisis on Wall Street.

McCain’s ad begins, “Barack Obama: Born of the corrupt Chicago political machine.” That’s an inaccurate statement - Obama wasn’t a machine candidate in the state Senate or in the U.S. Senate primary. However, he has been backed by Chicago Mayor Richard Daley and other establishment Democrats since he got the Senate nomination in 2004 and has worked with them since being elected.

The ad goes on to list establishment Democrats and their connection to Obama - some stronger than others.

It is true that Obama’s fundraiser Tony Rezko is a convicted felon. And his political mentor, state Senate President Emil Jones, has an array of relatives with state jobs, arranged for his son to take over his Senate seat next year and has dragged his feet on ethics legislation.

Obama did endorse his fellow Illinois Democrat Gov. Rod Blagojevich for re-election despite questions about his ethics, but the two are not particularly close. It’s also true that William Daley has been an adviser. But it’s not surprising Obama would seek economic advice from a former Commerce secretary.