Sen. Jeff Bingaman of New Mexico to retire

WASHINGTON -- The news just keeps getting worse for Senate Democrats.

In a surprising move, New Mexico’s Jeff Bingaman, who’s served in the Senate for almost 30 years, is expected to announce later Friday that he will not run for reelection in 2012.

The retirement of Bingaman, the fifth-most-senior Democrat in the chamber, is a blow to a party already reeling from last week’s decision by Sen. Jim Webb of Virginia to not seek a second term.

Democrats must defend 23 Senate seats next year -- and New Mexico had not been considered an anxiety-producing race on the order of coming battles in Missouri, Montana, Nebraska, Ohio and elsewhere. But Bingaman’s move could push that contest into the foreground as well.

The Land of Enchantment is in flux politically. Democratic Gov. Bill Richardson, who dominated the state’s politics for eight years, ended his term last year with low approval ratings and was replaced by a Republican, Susana Martinez, who is viewed as a rising star in the party. The 2010 elections also allowed GOP Rep. Steve Pearce to reclaim his old congressional seat from Democrat Harry Teague.

The timing of Bingaman’s announcement, however, gives Democrats plenty of time to find a competitive candidate. A recent survey by Public Policy Polling suggested that two young Democratic congressmen, Martin Heinrich and Ben Ray Lujan, match up well against potential Republican entrants such as Pearce and former Rep. Heather Wilson.

A wild card might be former Gov. Gary Johnson, a libertarian on the order of Rep. Ron Paul (R-Tex.). Johnson is also considering a presidential bid.

The Public Policy Polling survey showed that Bingaman, 67, likely would have coasted to reelection. With his retirement, the environmental lobby loses a key ally. Bingaman chairs the Energy and Natural Resources Committee and has long been an advocate of legislative attempts to curb greenhouse gases.

james.oliphant@latimes.com