Updated at 1:56 p.m. ET
Citing the political challenges he faced because of congressional redistricting, prominent Democratic Rep. Barney Frank on Monday announced he will not seek re-election in 2012.
"I don't want to be torn [between] a full-fledged campaign... and my obligation to my current constituents," Frank said from the Newton, Massachusetts City Hall.
The 16-term congressman first took office in Massachusetts' fourth district in 1980 and served as chairman of the House Financial Services committee from 2007 to 2011, during which time he spearheaded work on the landmark Dodd-Frank financial regulation legislation, which rewrote the rules for Wall Street after the 2008 financial crisis.
The 71-year-old congressman faced one of his toughest re-election bids in 2010, when conservative groups madeto back his challenger, Republican Sean Bielat. Frank defeated Bielat, 53 percent to 43 percent. He faced a potentially even more difficult race in 2012, now that the 4th district has been redrawn to include more conservative towns.
Frank pointed out today that the new 4th district includes 325,000 residents he does not currently represent. "Nobody ought to expect to get elected without a contest," he said. He added, however, that "the fact that it's so new makes it harder."
Frank had already raised just over $760,000 for his next campaign, but he said today he'd have to raise a couple more million dollars in order to compete in the new district.
President Obama praised Frank for his more than three decades of service, saying the House of Representatives "will not be the same without him."
"Barney has been a fierce advocate for the people of Massachusetts and Americans everywhere who needed a voice," Mr. Obama said in a written statement, noting that Frank helped make housing more affordable and fought to end discrimination against lesbian, bisexual, gay and transgendered Americans.
Frank said he considered announcing that this would be his last term earlier but decided against it so his influence in Washington wouldn't be weakened. He said he was particularly concerned the new Republican House majority would leave military spending untouched as it cut other government programs and that the GOP would undo the financial reforms he worked to enact.
"A funny thing happened on my way to retirement," Frank said. "A very conservative Republican majority took over the House... [and] the things I fought hardest for could be in jeopardy."
Frank, considered the most prominent gay politician in the United States, is known as an outspoken liberal with a sharp tongue. His liberal positions have made him a of conservatives, particularly after the passage of the Dodd-Frank Act.
"I did not think I had lived a good enough life to be rewarded by having Newt Gingrich be the Republican nominee," Frank said, alluding to Gingrich's recent rise in the polls and the fact that many Democrats consider the former House speaker unelectable.
With respect to the issue of gay marriage, Frank said Gingrich, who has been married three times, "is an ideal opponent for us when we talk about just who it is threatening the sanctity of marriage."
Frank took another shot at Gingrich when asked whether he would work as a lobbyist after retiring from Congress. "I will neither be a lobbyist or a historian," Frank said, alluding to Gingrich's claims that he worked as a historian -- but not a lobbyist -- for mortgage giant Freddie Mac.
"There is no way I would be a lobbyist," Frank said, adding that one of the advantages of being out of Congress and away from K Street is, "I don't even have to pretend to be nice to people I don't like."
Frank said he intends to spend his retirement writing, teaching and lecturing.