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Ahead of this Tuesday's election, campaigns and many outside groups have flooded some political races with cash. One of the most expensive congressional races in the country is in Sacramento, California in the newly re-drawn 7th District. That's where an incumbent and a leader of the House Republicans faces a strong challenge from an Indian-American physician. As NPR's Richard Gonzales reports, this is not their first electoral face-off.

RICHARD GONZALES, BYLINE: Dan Lungren is a Republican who's been in and out public office since 1979. He represented a Southern California district in the '80s, served as the state's attorney general for eight years, and then returned to Congress to represent the Sacramento area in 2004. These days, Lungren tells a friendly audience, he's still the same pro-business, limited government conservative he's always been.

REPRESENTATIVE DAN LUNGREN: There's a reason people are leaving California going to Texas, leaving California going to Nevada, and it's not for the weather. And so, I make no apologies whatsoever that I am all about more jobs, not more taxes.

GONZALES: That message played well in the past when his district was slightly more conservative, but now Lungren finds himself with a big target on his back.

LUNGREN: Just to let you know, I was informed before I came over here, more money's been spent against me in this race than any other candidate for Congress in the country.

GONZALES: At least that was true on the day he gave this speech. Since then, other races have become more expensive. But it's true that Democrats and outside PACs have spent more than $4.5 million trying defeat Lungren. Some of that money buys ads accusing him of being in the pocket of Wall Street and big oil. Then there's this one by a Democratic-backed superPAC, criticizing Lungren for his opposition to stem cell research.

UNIDENTIFIED WOMAN #1: This is Representative Dan Lungren.

UNIDENTIFIED CHILD: He's running for Congress.

UNIDENTIFIED MAN: He voted against embryonic stem cell research.

UNIDENTIFIED WOMAN #2: Is he a doctor?

GONZALES: The beneficiary of this ad is a doctor. He's a first generation American and his name is Ami Bera.

AMI BERA: We've got our secret weapon and it is all of you. You guys are the reason why we're going to win this thing. This is going to be one of the most important races in the country.

GONZALES: Bera, the Democrat in this race, is talking to a crowded room of phone volunteers. He ran against Lungren two years ago and lost. But Bera's back for a rematch in a re-drawn district where registered Democrats have an edge of 2 percentage points. In the closing days of the campaign, he's making a strong pitch to independent voters, telling them Lungren's too ideological.

BERA: Leadership is about saying I may disagree with you but let's figure out where we agree, let's build on those ideas and let's go out and serve the citizens of this country and the residents of this community. So, you know, I think Dan Lungren is going to lose because it is a failure of leadership.

GONZALES: But Bera's also the target of a lot of outside money, nearly three million dollars, that pay for ads like this one.

UNIDENTIFIED WOMAN #3: When you go in that voting booth, you need to know who you're voting for.

UNIDENTIFIED MAN #2: Ami Bera supports the health care law which will increase taxes on California families and businesses and cut $716 billion from Medicare. Californians just can't risk Ami Bera in Congress.

GONZALES: All the outside money underscores a fact that this Sacramento area district was designed to produce tight races, says University of Southern California political analyst Dan Schnur.

DAN SCHNUR: This is precisely the type of district that Californians thought they were getting when they supported a change in the re-districting rules and gave the responsibility to an independent commission. And that's not to say that they were looking to endanger more Republican incumbents, rather they just wanted to see more competitive races from candidates on both sides of the aisle.

GONZALES: Schnur says that makes California's 7th Congressional district exactly the kind of suburban swing district that might help determine the control of the House of Representatives. The candidates themselves say this race is too close to call.

Richard Gonzales, NPR News. Transcript provided by NPR, Copyright NPR.