A new ad by John McCainJohn Sidney McCainCindy McCain says no one in Republican Party carries 'voice of reason' after husband's death Anti-gun violence organization endorses Kelly's Senate bid McCain's family, McCain Institute to promote #ActsOfCivility in marking first anniversary of senator's death MORE's campaign tries to tie Barack ObamaBarack Hussein ObamaDemocratic governors fizzle in presidential race Obamas reportedly buying Martha's Vineyard mansion Trump has 62 percent disapproval rating in new AP poll MORE to Chicago politicians enmeshed in ethics controversies.

The ad features a clip of Obama saying that he hails from Chicago, followed by photos of Illinois Gov. Rod Blagojevich (D), Chicago Mayor Richard Daley (D) and convicted felon and fundraiser Antoin Rezko.

"Barack Obama, born of the corrupt Chicago political machine," a narrator intones.

McCain's campaign said the ad will run nationally, but it didn't say how much it would spend to air it and whether it would run on broadcast or cable channels.

Obama's campaign has called the spot "false" and highlighted a report that McCain's campaign manager, Rick Davis, was paid to lobby on behalf of embattled mortgage companies Fannie Mae and Freddie Mac.

"It's no coincidence that on the very day newspapers reported that John McCain's campaign manager was paid $2 million to lobby against tighter regulation of Fannie Mae and Freddie Mac, the McCain campaign would launch this false, gratuitous attack," said Obama spokesman Bill Burton in a statement. "Barack Obama was elected to the Illinois Senate as an independent Democrat. He took on the Chicago Democratic organization in a primary to win a seat in the US Senate. And in both Illinois and Washington, he has challenged the Old Guard for landmark ethics reforms."

Read the ad's transcript and watch the ad below.

Script For "Chicago Machine" (TV :30)

ANNCR: Barack Obama.

Born of the corrupt Chicago political machine.

BARACK OBAMA: In terms of my toughness, look first of all, I come from Chicago.

ANNCR: His economic adviser, William Daley. Lobbyist. Mayor's brother.

His money man, Tony Rezko. Client. Patron. Convicted Felon.

His "political godfather." Emil Jones. Under ethical cloud.

His governor, Rod Blagojevich. A legacy of federal and state investigations.

With friends like that, Obama is not ready to lead.

JOHN MCCAIN: I'm John McCain and I approve this message.