Obama's other woman

(CNN) -- Barack Obama is a married man but there's another woman with a hold on him that his wife can never match: she runs the House.

She is Nancy Pelosi, the Democratic speaker of the House of Representatives, the most powerful woman in Washington and lately, a target for Republicans.

Pelosi is easy to spot in any crowd of U.S. politicians; she's the small brown-haired woman in the smartly tailored suit.

Conservatives like to stereotype some Democrats as rich, isolated and out-of-touch. As the wife of an affluent investment banker, the always expertly coiffed Pelosi looks like exactly the kind of "Limousine Liberal" they're talking about.

Ironically, it's money that makes her powerful. Under the U.S. constitution, the president can't spend a penny without the permission of Congress.

Within the Congress, the Senate has its own powers but the House is the place where taxes and spending start. So almost every one of Obama's plans needs a push from Pelosi.

Maybe that's part of the reason she's in trouble right now.

The issue isn't really part of her daily duties: "waterboarding" and other extreme interrogation tactics used against prisoners in the Bush era.

Obama ordered an end to the harsh methods, but Republicans are asking why Democrats who knew about them years ago didn't try to stop them then.

Pelosi was one of a handful of lawmakers who was briefed by the Central Intelligence Agency in 2002, but she now accuses the agency of lying to her and hiding what it was doing.

Republicans have been attacking Pelosi for making unsubstantiated and damaging accusations against a crucial national security agency.

The man who once had her job, former Republican speaker Newt Gingrich, says Pelosi is lying in a way that is "despicable, dishonest and vicious."

Whether or not he's right, it's smart politics. Obama is still remarkably popular. Most of the country hopes that he'll succeed in rebuilding the economy and ending the war in Iraq.

If the president is immune to most easy attacks from the opposition, it needs to find someone who isn't.

Pelosi is a crucial part of his plans. As potential targets go, with her nearly perfect hair and nearly perfect clothes, Pelosi is nearly perfect.