In Alaska's Senate Race, Republican Sullivan Upsets Incumbent

Dan Sullivan, a Republican whose campaign was supported by both Mitt Romney and Sen. Ted Cruz, has beaten Democratic incumbent Sen. Mark Begich to win the race for U.S. Senate in Alaska, according to The Associated Press.

That expands the GOP's Senate majority to 53 seats.

The late call in Alaska's race is due to a close margin on Election Day and the time required to collect all the ballots from the state's far-flung polling places. The tally saw Sullivan's initial lead of more than 8,000 votes shrink some — but not enough to give Begich the win.

The Senate seat was hotly contested, as the AP reports:

"Tens of millions of dollars were pumped into the state, with Republicans seeing Begich as vulnerable and Democrats trying to hold the seat Begich won in 2008. Voters were barraged by calls and ads, which many said they were turned off by."

The loss means Begich's tenure in the Senate will last only one term; he narrowly defeated Sen. Ted Stevens in 2008.

One more Senate race remains outstanding in this year's midterms: Louisiana Sen. Mary Landrieu, a Democrat, will face Republican Rep. Bill Cassidy in a runoff vote on Dec. 6.