Rep. Barney Frank (D) of Massachusetts, one of Congress’ few truly great lawmakers, has decided he’s had enough.

US Representative Barney Frank, the state’s highest profile congressman and one of the nation’s leading liberal voices, has decided not to seek reelection next year.

A close adviser told the Globe today that the new district in which Frank would have to run next year was a major factor in his decision. While it retained his Newton stronghold, it was revised to encompass more conservative towns while Frank also lost new Bedford, a blue-collar city where he spent a lot of time and became a leading figure in the debate over fisheries.

Frank, who was first elected in 1980, will reportedly make the announcement at a 1 p.m. press conference in his district.

His retirement comes just a year after a relatively tough re-election fight — Frank won by “only” a 10-point margin, making the 2010 race the toughest of his career — which would have grown even tougher still in 2012 thanks to an unfriendly redistricting process.

Given this, Frank’s departure will give Republicans a pick-up opportunity in the redrawn 4th congressional district, though it’s unclear just yet who the leading candidates will be. Roll Call reported this morning that Alan Khazei, who recently dropped his U.S. Senate primary bid, will likely be in the mix.

But putting all of that aside, it’s worth pausing to appreciate the fact that Barney Frank has had an extraordinary and consequential career — the nation is better off for his efforts — and Capitol Hill is losing its smartest lawmaker.

In Washington, he will be missed, and we can only hope Frank’s post-Congress career includes time for his upbraiding of Republicans and reporters, if we’re lucky, on a full-time basis.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.