* Sherman-Berman contest bitter in 30th District
* Congressional campaign marred by debate standoff
* Long-serving Democrats face losing long-held seat
LOS ANGELES, Nov 3 (Reuters) - Two rival Democratic congressmen are proving that similar politics does not guarantee amity in a hard-fought California race on the edge of Hollywood that has at times resembled reality television more than a congressional campaign.
The contest pits U.S. Representative Howard Berman, the ranking Democrat on the House Committee on Foreign Affairs, against Representative Brad Sherman, a senior member of the Financial Services Committee first elected in 1996.
The Sherman-Berman race is a result of California's new electoral landscape, which combines redrawn political districts and a new top-two primary system. The contest is one of eight U.S. House races in the most populous U.S. state that pit two candidates of the same party against each other.
The contentious Sherman-Berman race has stood out for the bitterness of its tone.
Sherman, 58, and Berman, 71, have represented adjoining districts in the San Fernando Valley, a suburb of Los Angeles, but were forced to compete in the same district.
At a rowdy debate this month, Sherman put his arm around the older, slighter Berman, and not in a nice way. It happened on stage at a community college, after Berman stepped toward Sherman, who then put his arm around his fellow congressman and said, "You want to get into this?"
Video of the unusually aggressive encounter went viral on the Internet.
If that was a low point, the nearly $14 million battle has hit a high mark by ranking as one of the most expensive congressional races of 2012.
Berman's campaign has spent $5.4 million and Sherman's has shelled out $4.9 million, with outside groups pouring in another $3.4 million, according to the Center for Responsive Politics. The group ranks the contest as the fifth most expensive U.S. House race in the nation when outside money is factored in.
Democrats would rather see that cash, and the creative campaign mailers featuring everything from puffer fish to fake baseball cards, used against rival Republicans.
"It's not like Howard and I get together at the ... Marriott for drinks on a Friday evening," Sherman joked in a telephone interview, before acknowledging his working relationship with Berman was "not at a high point."
Neither man had faced a tough campaign challenge since landing in Congress, so neither has come this close to losing his long-held seat.
The party-on-party House contests were created by a combination of an independent commission redrawing California's political districts, and a new voter-approved primary system that advances the top two vote getters to the November election, regardless of party.
Since the duo advanced easily in the June primary for 30th District, their campaigns have been forced to compete for Republican and independent voters, because there is no Republican on the ballot.
Berman, first elected to Congress in 1982, has won an endorsement from prominent Republican U.S. Senator John McCain of Arizona - a coup that would have been unlikely had he faced a Republican challenger.
Berman has also sought to capitalize on fallout from the Oct. 11 debate in which Sherman yanked and shouted at Berman.
"Valley voters have seen the real Brad Sherman," Berman campaign senior adviser Brandon Hall said in a statement. Berman's campaign also produced a TV ad called "Unhinged" to zero in on Sherman's actions.
Sherman denied that his confrontation with Berman was a physical altercation. "I would call it an unfortunate distraction," Sherman said.
Berman was not available for an interview.
Douglas Johnson, a fellow at the Rose Institute of State and Local Government at Claremont McKenna College, said the debate fracas stands out. "I don't know that I've ever seen anything like that," he said.
Despite the animosity, Berman and Sherman have similar records as liberal Democrats, sharing views on issues like abortion, Israel, the environment and gay rights.
One difference was on the Troubled Asset Relief Program, a federal bailout vehicle launched during the financial crisis. Sherman voted against it in 2008 while Berman was in favor.
Despite their similar views, Johnson said redistricting and the new primary system have shaken things up.
"We're seeing this with Berman and Sherman, where ... the winner will be the one who can attract the most Republicans," he said. "Those cross-party appeals really force the candidates to moderate their views to some degree."
Sherman, seen as having an advantage because he has more overlap with his old district, said the new primary system was mainly designed to lead to more moderate candidates winning election to the state legislature, but that it could be a model for congressional races elsewhere.
"Let's test it here in California, but God knows we need to do something to end gridlock in Washington," said Sherman, who a SurveyUSA poll of 800 registered voters last month showed with 44 percent support versus 33 percent for Berman. The poll had a 3.9 percent margin of error.
At the same time, Sherman said he has not shifted to the right politically. "I'm not moving at all," he said.