The popular Surf City official is the Democratic hope to unseat GOP incumbent Rep. Dana Rohrabacher -- seeking his 11th term -- in an underdog campaign some observers believe may succeed.
Rohrabacher's critics grumble that he has accomplished little in two decades on Capitol Hill and doesn't bring much federal money to the district, which squiggles from Palos Verdes through parts of San Pedro and Long Beach, with the bulk made up of Huntington Beach, Costa Mesa and other Orange County cities.
The congressman argues that positions such as his consistently hard-line stance on illegal immigration have endeared him to constituents in a solidly conservative district where registered Republicans outnumber registered Democrats by 56,000.
Yet in a tumultuous election year in which Republican officials across the country are looking over their shoulders, Cook is considered by some to be a contender.
Even Rohrabacher acknowledges Cook's strength as a candidate: "I've paid more attention to this race than I have in the past," he said in a recent phone interview from Washington. But, he adds, his Reagan-style brand of positive conservatism is a better fit with the district, "compared to someone who would be on the liberal left."
The two don't have much common ground.
Talk to Cook for more than five minutes, and she launches into an impassioned discourse on her favored issue: the decline of the world's oil supply. She'll whip out graphs from speeches she gives on the topic. Her cherry-red Prius' vanity plate reads "NRGMAVN," for "Energy Maven."
"All that government does is going to be dependent on whether we have affordable, cheap energy," Cook said in a recent interview. Cook cut her political teeth nearly 20 years ago leading a surprising grass-roots victory to rein in development of open space in Surf City. She later went to law school to further her efforts to preserve local wetlands.
Rohrabacher, on the other hand, questions whether global warming is a man-made phenomenon.
Despite an easy primary win, Cook must overcome the district's formidable Republican registration numbers. There are nearly 124,000 registered Democrats, close to 180,000 registered GOP voters, and almost 75,000 voters who declined to state a preference. That leaves Cook with little room for error to beat Rohrabacher.
"This is a very upscale, very white-collar district," said Stu Rothenberg, a nonpartisan political analyst. In 2004, 57% of voters favored President Bush. "It is the epitome of a Republican district."
State Republican leaders aren't losing sleep yet, either: "We've always felt very comfortable with the ability of Dana Rohrabacher to hold onto that seat," said Hector Barajas, spokesman for the state GOP.
As a result, Cook is on national Democrats' radar but hasn't drawn the financial backing of the Democratic Congressional Campaign Committee, which has about $45 million on hand to tip close races. Rohrabacher's war chest of more than $323,000 on hand dwarfs the $21,000 Cook has available.
But the idea of an upstart Democrat toppling a Republican candidate in a conservative stronghold isn't farfetched: This year, Democrats have snatched seats out of GOP hands in Mississippi, Illinois and Louisiana.
Those upsets, coupled with the president's dismal approval ratings, have political observers wondering if this could be Cook's year.
"Debbie Cook is a serious candidate, with serious money, with serious name recognition at a time when the country is looking for change," said Mark Petracca, chairman of the political science department at UC Irvine. Cook, who touts her credentials as policy wonk and a fiscal conservative, was elected to the council in 2000, has twice served an annual stint as mayor and won Tuesday's Democratic primary with 80% of the vote. Rohrabacher won his primary with 87%; nearly twice as many people cast ballots in his race.
But Cook's hometown popularity doesn't guarantee her votes: "Voters are sophisticated," said Scott Baugh, chairman of the Orange County GOP. "What they like on the retail level with local government is not necessarily what they want at the wholesale level with federal government."
The numbers don't faze Cook. "There are a lot of Republicans in this town that are going to vote for me," Cook said. "There is so much widespread disappointment in the current representative; he's extremely divisive . . . he actively works against the people in his own district."
Rohrabacher dismisses Cook's assessments as ill-informed. "I'm very frank with people when I disagree with them," he said. But "an idea that I don't meet with people -- that's ridiculous."
A member of the House committees on Foreign Affairs and Science and Technology, the 60-year-old surfing congressman cites work to decrease water pollution and alleviate truck congestion at the ports as projects he's supported.
"His focus has just been more on issues than on infrastructure," said Matthew Cunningham, online editor of conservative political blog RedCounty.com. "There are certain politicians that become part of the fabric," said Chris Epting, a Huntington Beach columnist and local historian. "They become really easy to vote for just by virtue of the fact that everybody feels like they know him."
In just four months of campaigning, Cook, 54, has had to deal with a few controversies.
Orange County GOP operative Mike Schroeder filed a lawsuit against her in March, saying that her mayoral title on the ballot violated election code because the position is rotated among the City Council. The suit was dismissed. Cook also came under fire when the Orange County Register wrote about thousands of dollars she had invested in fuel companies such as BP, Chevron, ExxonMobil and Royal Dutch Shell.
"I'm just as entitled as any other capitalist to invest my retirement money in a way that I think it'll actually be there," Cook said. "If I were a gambler and I were to go to Vegas, does that mean I support organized crime because I gamble?"
In the meantime, Cook is working to boost her visibility beyond Huntington Beach.
"No one thought Loretta Sanchez could beat Bob Dornan," a GOP congressman who represented Orange County from 1985 to 1996, said Fred Smoller, an associate professor of political science at Chapman University. "All of a sudden, the electorate can surprise you."