Nebraska Attorney General Jon Bruning (R) announced on Friday that he is considering a 2012 challenge to Sen. Ben Nelson (D).

“I can’t imagine any conditions under which I would not run,” Bruning said in a morning press conference, according to the Lincoln Journal Star.

Bruning’s announcement is the latest domino to fall in the quickly developing Senate race as Republicans start to think about knocking off enough Democrats to win control of the Senate in the next cycle.

Nebraska Gov. Dave Heineman (R), who was widely expected to oppose Nelson and was polling well against the incumbent Democrat, announced this week he would not run for Senate.

Nelson told Roll Call in an interview this week that he would remain a Democrat, not switch to the GOP as some had speculated thanks to his conservative voting record.

Bruning, 41, would present a considerable challenge to Nelson, 69, a former Nebraska governor who was first elected to the Senate in 2000 and is unpopular in the Cornhusker State. A former state senator, Bruning was first elected attorney general in 2002 and was unopposed in 2006 and 2010. He was elected president of the National Association of Attorneys General in 2009.

In 2008 he planned a run to replace Sen. Chuck Hagel (R), raising money through an exploratory committee, but dropped out after a few months when former Gov. Mike Johanns (R) ran instead. Johanns won the race and is now serving in Washington, D.C. The Omaha World-Herald reported that Bruning raised $1 million for the short-lived 2008 bid and that he told the press he has $600,000 left from that race in a federal account.

Bruning Campaign Manager Andrew Northwall, who oversaw his attorney general race and transitioned to the Senate campaign this week, said his boss doesn’t expect to cede the race to another Republican this time. He said the campaign hasn’t invested in polling yet.