Democratic Sen. Mark Begich brought in more than $300,000 in the fourth quarter, giving him almost $1 million in cash on hand to kick off his 2014 re-election campaign cycle.

Begich is one of six Senate Democrats seeking re-election in a state the president lost last year, making him one of his party’s most vulnerable members of the cycle. Roll Call rates this race as a Tossup.

Several Republicans are taking serious looks at challenging him in 2014. Potential GOP opponents include Lt. Gov. Mead Treadwell, who said in December that he formed an exploratory committee for the race, and 2010 Senate nominee Joe Miller.

Any challenger would start off well behind the first-term senator in fundraising with the advantages of incumbency, plus Begich’s strong fourth-quarter haul.

According to his year-end report to the Federal Election Commission, Begich raised $336,000 from Oct. 1 to Dec. 31. He spent just $65,000 in the fourth quarter and had $952,000 left in cash on hand.