Republican U.S. Senate candidate Joe Miller  (R). (AP Photo/Mark Thiessen)

Tea party candidate Joe Miller said Thursday that he plans to support the Republican nominee for U.S. Senate in Alaska, a break for the GOP in one of the most crucial contests in the battle for the Senate majority.

In effect, Miller -- a long-shot candidate for the GOP nomination -- ruled out an independent bid that could have attracted voters would otherwise support the GOP nominee. Even if he didn't run as an independent, Miller could have caused the nominee some headaches with arch-conservative voters by refusing to fall in line.

He made his announcement in a debate and on Twitter.

Miller is running for the nomination against former attorney general Dan Sullivan and Lt. Gov. Mead Treadwell. Sullivan is favored to win.

Miller ran for Senate in 2010, defeating Sen. Lisa Murkowski in the Republican primary. But she waged a write-in effort and won the general election over a deeply flawed Miller campaign.

The winner of the primary will face Sen. Mark Begich (D), who is gearing up for a competitive race. Begich is one of four Senate Democrats running for reelection in a state Mitt Romney won.

Senate Republicans need to gain six seats to win the majority.