Editor's note: Campbell Brown anchors CNN's "Campbell Brown: No Bias, No Bull" at 8 p.m. ET Mondays through Fridays. She delivered this commentary during the "Cutting through the Bull" segment of Tuesday night's broadcast.

CNN's Campbell Brown complains about Barack Obama's switch on financing.

(CNN) -- You may have heard that Wednesday night Barack Obama will be on five different TV networks speaking directly to the American people.

He bought 30 minutes of airtime from the different networks, a very expensive purchase. But hey, he can afford it. Barack Obama is loaded, way more loaded than John McCain, way more loaded than any presidential candidate has ever been at this stage of the campaign.

Just to throw a number out: He has raised well over $600 million since the start of his campaign, close to what George Bush and John Kerry raised combined in 2004.

Without question, Obama has set the bar at new height with a truly staggering sum of cash. And that is why as we approach this November, it is worth reminding ourselves what Barack Obama said last November.

One year ago, he made a promise. He pledged to accept public financing and to work with the Republican nominee to ensure that they both operated within those limits.

Then it became clear to Sen. Obama and his campaign that he was going to be able to raise on his own far more cash than he would get with public financing. So Obama went back on his word. Watch Campbell Brown on Obama's campaign financing »

He broke his promise and he explained it by arguing that the system is broken and that Republicans know how to work the system to their advantage. He argued he would need all that cash to fight the ruthless attacks of 527s, those independent groups like the Swift Boat Veterans. It's funny though, those attacks never really materialized.iReport.com: Your chance to ask Obama a question

The Washington Post pointed out recently that the bad economy has meant a cash shortage among the 527s and that this election year they have been far less influential.

The courageous among Obama's own supporters concede this decision was really made for one reason, simply because it was to Obama's financial advantage.

On this issue today, former Sen. Bob Kerrey of Nebraska, an Obama supporter, writes in The New York Post, "a hypocrite is a person who puts on a false appearance of virtue -- who acts in contradiction to his or her stated beliefs or feelings. And that, it seems to me, is what we are doing now."

For this last week, Sen. Obama will be rolling in dough. His commercials, his get-out-the-vote effort will, as the pundits have said, dwarf the McCain campaign's final push. But in fairness, you have to admit, he is getting there in part on a broken promise.

The opinions expressed in this commentary are solely those of Campbell Brown.

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