All day the titles of one Doors song and two Who songs (The Doors' "5 to One," and the Who's "905" and "5:15") have been ringing in my head.

Why?

No other reason than to keep my toe-tapping to the relentless back-and-forth today between the Obama and Edwards camps over two union-affiliated 527 groups now airing more than $1 million in radio ads in Iowa that indirectly benefit Edwards. (Well, the fact that all three songs have "5" in them may have something to do with it and that all are under-appreciated parts of both bands' discography -- but let's not go there loyal Bourbon Room readers).

The groups (the 527s, not The Doors or the Who) are loosely backed by Iowa members of the Service Employees International Union and the Steelworkers union. The SEIU-affiliated group is headed by Nick Baldick, a former top operative in Edwards' 2004 presidential campaign.

There's serious money behind these ads, more than $1 million by the Obama camp's count and that's enough to saturate the biggest media markets in Iowa -- as the groups no doubt intend to do.

In Oskaloosa, Obama came right to the edge of calling Edwards a fraud when he said Edwards should denounce and end the ads.

"You cant just talk the talk," Obama said with intensity. "The easiest thing in the world is to talk about change during election time. Everybody talks about change during election time, you've got to look at how they act when its not convenient, when its hard."

Edwards' first response?

He blamed Obama's complaints on a change of fortune in the Hawkeye state.

"Senator Obama's attacks seem to increase as momentum for our campaign grows," Edwards himself, not a spokesman, said in a statement.  "As for outside groups, unfortunately, you can't control them, but let me make it clear - I think money has corrupted our politics and these groups should not be a part of the political process."

"Can't control" is 100 percent legally true, as everyone in this game knows.

No one controls a 527 except those who bankroll it with unlimited and undisclosed donations and the operatives who cash those checks.

But as camp Obama swiftly pointed out, Edwards demanded in 2004 that President Bush step away from such no-can-touch legal arcana and stop the Swift Boat Veterans For Truth ads against John Kerry.

Obama's chief spokesman Bill Burton gleefully e-mailed these Edwards' riffs on Bush and the Swift Boaters.

“There's one person, one person who can put an end to this today if he had the backbone, the courage, the leadership to do it. And that person is George W. Bush," Edwards said in an Associated Press report on Aug. 24, 2004. "Every day that this goes on and the president refuses to say stop these ads,we're learning more and more about the character of George W. Bush.”  Reporters traveling with Edwards today hounded him on this issue. By sunset Edwards not only told reporters he would call for the union-affiliated ads to be pulled, his campaign farily trumpeted the turn-around.Here is part of an Edwards campaign press sent 5:11 p.m. EST:

EDWARDS: STOP THESE ADS

Edwards calls on 527 groups to stop running ads

Des Moines, Iowa – Today, after an event in Coralville, Iowa, Senator John Edwards called on 527 groups to stop running ads: 

“I do not support 527 groups. They are part of the law, but let me be clear: I am asking this group and others not to run the ads.  I would encourage all the 527s to stay out of the political process.”

The 527 scrum now over, let's quickly analyze it.

Obama wins by forcing Edwards to reverse earlier statements. But don't count Edwards a loser. Edwards is now a big problem for Obama. Team Obama knows Edwards has a top-flight Iowa organization, knows Edwards is the second choice of clear majority of likely Democratic caucus-goers (every polls shows this), and, most frightening of all, Obama's team knows if Hillary can't win Iowa her next choice is to have Edwards win. 

If Edwards wins and Hillary finishes second and Obama third, Clinton can fight Edwards on stronger ground in New Hampshire and without the handcuffs of spending limits that Edwards must live with. 

Obama can't afford to allow a single Edwards advantage to go unchallenged. And, of course, Edwards can call on the ads to be withdrawn but that doesn't mean they will be because, as he correctly said, election law forbids any direct coordination between a candidate and a 527 -- even if that coordination is to pull ads from the air. 

The larger point of today's clash -- other than putting three great rock songs in my head -- is that Obama fears Edwards and can't dare let a single tactical advantage of his go without a fight. Obama fought. He fought hard and, on points, he won. 

But as he returns to his corner, Obama knows Edwards has staying power and will fight to the death in Iowa. As The Bourbon Room has noted before, if Edwards doesn't win Iowa, he's done. 

Obama can take a second place finish in Iowa to Edwards, but not a third to Edwards and Clinton. Hence the pre-Chirstmas ferocity of his response.  

Mike Emanuel currently serves as chief congressional correspondent for FOX News Channel (FNC). He joined FNC in 1997 as a Los Angeles-based correspondent.