SAN FRANCISCO (AP) — California, once an afterthought in the battle for control of Congress, has become a top target for deep-pocketed political action committees and other groups in an all-out effort to win districts stretching from the farming towns of the Central Valley to the beach communities of San Diego.
Since an independent panel recast California's political boundaries two years ago, the state's newly drawn congressional districts now comprise the most competitive House landscape in the nation and are attracting money at an unprecedented clip — more than $45 million so far.
With less than a week until Election Day, that spending is surging as more than 80 outside groups and independent super PACs seek to sway the makeup of the nation's largest congressional delegation, which has 34 Democrats and 19 Republicans.
Even in an age of freewheeling political spending blessed by the U.S. Supreme Court, no other state has come close to California in the sheer volume of outside spending on House seats. Illinois, the state with the next highest level of spending, had attracted $34.6 million by Monday, according to the nonpartisan Center for Responsive Politics, which tracks campaign spending.
In several California races, spending by outside groups appears to be on track to eclipse the money being spent by campaigns, meaning a candidate's voice might be drowned out — or amplified — by ads, phone calls and mailers financed by people or groups that are supposed to have no direct tie to the person on the ballot.
"2012 has become the Wild West," said Steve Frank, a longtime conservative activist from suburban Los Angeles.
Most of the spending is coming from the official campaign arms of the House Democrats and Republicans, which have built a stronger West Coast presence to sustain operations beyond 2012. The National Republican Congressional Committee had spent $10.3 million by Monday, compared to the Democratic Congressional Campaign Committee's $6.9 million.
The fourth-largest spender, the U.S. Chamber of Commerce, reported sinking nearly $3 million into California House races, but a chamber official said the group has spent even more on other political efforts that did not require disclosure.
Democrats need to gain 25 seats nationwide to retake the House majority this year, an uphill battle they're not expected to win in November. But most political professionals are thinking ahead to 2014, said Rob Engstrom, the chamber's national political director.
"No other state has more competitive House races than California, so that is a very, very big footprint nationally," said Engstrom. "That explains why we have made this huge financial commitment there and will keep doing so over the next decade."
Outside are dueling in several congressional districts near Sacramento.
In one, Democratic challenger Ami Bera is making a second try at unseating Republican incumbent Rep. Dan Lungren. In 2010, Bera, a physician, said a crucial slice of voters flocked to Lungren after American Crossroads, a conservative super PAC co-founded by GOP political strategist Karl Rove, bought a round of television ads attacking Bera in the campaign's final weeks.
This cycle, dozens of super PACs on Bera's side are fighting back with anti-Lungren ads.
"The difference is this time these outside groups are coming in on both sides," Bera said. "You never know at what point you have diminishing returns and there is so much money moving in the system that people stop paying attention."
Lungren was glib about why he believes Democratic-leaning groups were pouring money into the 7th Congressional District, the third-most expensive House race nationwide.
"Maybe because I'm the geographically closest incumbent to Nancy Pelosi, and I've been rather outspoken in my differences with her," Lungren said. Pelosi represents San Francisco.
Two other California House races — the 10th District near Modesto and the San Diego-area's 52nd District — also are among the top 10 most expensive nationwide.
In San Diego, where Republican Rep. Brian Bilbray is trying to fend off Democrat Scott Peters, outside groups as varied as Planned Parenthood and Americans for Tax Reform, headed by low-tax crusader Grover Norquist, had spent more than $7.4 million through Monday.
The campaigns together doled out $4.1 million through Sept. 30, the most recent figures available.
"We can't match on our own what's being spent by the outside groups," said Peters spokeswoman MaryAnne Pintar, referring to the profusion of TV ads and mailings in the district, most of them negative. "Every day there is something new to respond to."
Political party structure was shaken by the Supreme Court's 2010 Citizens United decision, which along with other federal rulings stripped restrictions on political contributions from corporations, labor unions and millionaires and billionaires.
Checks from wealthy donors that once would have been cut to Republican or Democratic organizations now go to super PACs or charities formed under the federal tax code, which have no limits on spending.
California's new primary system, which sends the top two finishers to the runoff regardless of party affiliation, also has attracted outside funding to a handful of races pitting candidates of the same party against one other.
One super PAC bankrolled by Hollywood producer Jeffrey Katzenberg is aimed at supporting Democratic Rep. Howard Berman, as he battles incumbent Democratic Rep. Brad Sherman over a San Fernando Valley seat.
Stanford physicist Charles Munger Jr., the son of billionaire Berkshire Hathaway Inc. Vice Chairman Charles Munger, worked with former Republican state lawmaker Abel Maldonado as part of the effort to establish the new primary system, which is intended to open the way for more centrist candidates.
Maldonado, who is running against Democratic Rep. Lois Capps for a Central Coast congressional seat, is getting help from Munger's super PAC, Spirit of Democracy America. It had funneled more than $1.4 million into the race.
"There's so much at stake this year and there is so much more money flowing into these critical races that we used to not pay much attention to," Jaime Regalado, emeritus professor of political science at California State University, Los Angeles.