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Barbara Boxer to retire, tipping off blockbuster Senate race

After more than two decades in the Senate, California Democrat Barbara Boxer is retiring -- setting up a blockbuster race to replace her.

Democratic California Sen. Barbara Boxer is not running for reelection in 2016, she announced in a video Thursday, setting up a mammoth race for the first open Senate seat in the Golden State in more than two decades.

Reactions poured in quickly from top Democrats, who called Boxer's retirement a major loss to the party and the Senate. "Barbara Boxer is more than a Senator -- she’s an institution," said President Obama. Vice President Joe Biden said, "Barbara Boxer has been my soul mate in the Senate for a long time."

House Minority Leader Nancy Pelosi, Boxer’s fellow California Democratic senator, was stunned when reporters asked about the news during her weekly press conference. Pelosi said she missed a call from Boxer earlier in the day, assuming the senator “maybe wanted to have dinner tonight.” Pelosi added, “It’s a real loss. But God bless her for her decision.”

WATCH: Sen. Barbara Boxer takes on voting rights

Boxer, 74, said in a mock interview with her grandson, Zack, that her decision had nothing to do with her age. She also stressed that she will “never” retire, but wants to “come home” to California to continue her work. Boxer has been a progressive champion in the Senate on women's rights and the environment, among other issues.

Her retirement is the first major shakeup in years of California Democratic politics, which has been dominated by the same crop of leaders for decades. It sets up what is sure to be a wild blockbuster of race — a slate of ambitious Democrats will likely be vying against each other for the first shot at an open Senate seat in the country's most populous state since the beginning of the Clinton era.

Fundraising records will be broken, shots will be fired, and most of it will be friendly fire as the state's new-ish “jungle primary” system allows two Democrats advance to the general election.

"I can see it getting very dirty," said Karl Frisch, a California native who worked for the state party and the Democratic Senatorial Campaign Committee before joining the public relations firm Bullfight Strategies in Washington D.C.

Possible Democratic contenders

The two brightest stars in the state at the moment are Attorney General Kamala Harris and Lieutenant Gov. Gavin Newsom.

The wrinkle is that they both share the same political consultant, Ace Smith and his partners at the San Francisco-based SCN Strategists, who also ran Gov. Jerry Brown’s reelection campaign last year. A third top contender could be former Los Angeles Mayor Antonio Villaraigosa, who also happens to have SCN as his consultant. Smith’s partner Sean Clegg served as Villaraigosa's deputy mayor.

Smith has assured msnbc in the past that Newsom and Harris will not run against each other, but did not return a request for comment Thursday. Other Democratic strategists in the state say Newsom and Villaraigosa are more interested in running for governor after Brown is force out of office by term limits 2018. 

One strategist who requested anonymity said Villaraigosa has privately told allies that his eye is on the governorship. Newsom, the former mayor of San Francisco, ran for governor in 2010 but quickly aborted when Brown got in.

Doug Herman, a Democratic strategist based in Los Angeles, called Boxer's retirement a “gold rush” for Democrats with statewide aspirations. “Kamala Harris is clearly well positioned to be a candidate in the Senate race,” he told msnbc, predicting a “fairly crowded primary.”

Harris could distinguish herself from other Democrats and attract national donors and attention as a women of color running for a seat in a chamber that lacks both. “She's the most likely to break through,” Frisch said.

Among members of Congress, Rep. Loretta Sanchez’s name is often mentioned, and she’s publicly expressed interest in the upper chamber — even as recently as last month. “I put it at 50-50 now,” a source with close knowledge of her thinking told msnbc. “Depends on how the field shakes out.”

Rep. Xavier Becerra, the chairman of the House Democratic Caucus, is also mentioned as a possible candidate, especially since Democrats are unlikely to regain control of the House anytime soon. Several other House Democrats, frustrated by a lack of upward mobility in Congress, could also consider throwing their hats in the ring.

Secretary of State Alex Padilla, newly elected Treasurer John Chiang and incoming Controller Betty Yee could also be in the running, while outgoing Treasurer Bill Lockyer has reportedly been stockpiling cash in his campaign account.

Los Angeles Mayor Eric Garcetti was also rumored to be interested in the job, but took himself out of the running. "I love my job and I love my city and I am committed to the work here. I will not run for Sen. Boxer's seat," he tweeted.

California also has a long history of wealthy candidates —from Michael Huffington to Meg Whitman to Kashkari — spending their own money on campaigns, though they tend to lose. Tom Steyer, the politically active billionaire could be the exception, but he, too, is rumored to more interested in a gubernatorial run than Senate one.

On the Republican side

The Republican bench, on the other hand, is decidedly barren. The only Republican to win statewide in California since 1998 was former Gov. Arnold Schwarzenegger, and Democrats have held all eight of California's lower elected statewide offices since 2002 almost entirely uninterrupted.

Winning the seat is a "very steep” climb for the GOP, especially in a presidential election year when Democratic turnout is expected to be high, acknowledged Sacramento-based Republican strategist Rob Stutzman.

“The only obvious candidate to me who could change that thinking is if Condi Rice would run. I think that would bend it a little bit and make it possibly competitive, but other than that," the prospects are not encouraging, he told msnbc.

"The only obvious candidate to me who could change that thinking is if Condi Rice would run."'

Rice, the former secretary of state under George W. Bush, teaches at Stanford.

In his reelection bid last year, Brown barely had to lift a finger to crush Republican Neel Kashkari, a former Bush administration official who appeared to be an attractive candidate. A month out from the election, Brown has spent just  $402,000 on his campaign and starred in zero campaign ads.

The most prominent GOP-elected official from California is Rep. Kevin McCarthy, who was just promoted to House Majority Leader — an arguably more powerful job than freshman senator.

State Assemblyman Tim Donnelly, a tea party Republican who came in third in the governor’s race behind Brown and Kashkari, might take a look, as could Fresno Mayor Ashley Swearengin, who had a surprisingly strong showing in the race for state controller last year.

One hope for Republicans is that the state’s new “jungle primary” system could split the vote in a wide Democratic field while the GOP unites behind a single challenger.

There’s even a “bizarre” scenario in which two Republicans make it to the general election by capturing more votes than any single Democrat in a fractured field, Stutzman noted, though he added that it’s highly unlikely.

The Golden State Challenge

No matter what, everyone agrees the race is going to cost a fortune.

“We're going to see incredible amounts of money flowing in,” said Darry Sragow, a Democratic strategist Los Angeles. He said he floated the prospect of raising $50 million, including outside money, to one potential candidate, “who looked at me like, you're out of your f**king mind."

But California has four of the country's biggest (and thus most expensive) media markets, its largest population, and third largest geographic territory. It’s essentially impossible to run a full campaign, including television advertising, field organizing, direct mail, and other programs everywhere, meaning candidates have to make hard choices about where to put their money. 

It costs $2.5 million to run a week’s worth of television advertising in California, which has four of the countries biggest media markets. That means a six-week primary campaign would cost $12 million to $15 million.

Boxer spent $28 million beating Republican Carly Fiorina in 2010 — and there was no primary.

One Democratic operative who asked not to be named expected $30 million will be the “table stakes” of a top-tier campaign, meaning the number could up from there.

While the state is usually too expensive even for deep-pocketed national super PACs to spend their precious resources, a California billionaire like Steyer could boost a candidate of their choosing with an outside group.

But no one really knows how much a campaign will cost, because there hasn’t been an open Senate seat since 1992 and the rules have changed dramatically since then. In state, there's the new primary system, and nationally, there’s the explosion of super PACs and other outside money.

One thing is for sure: Records will likely be broken.