WASHINGTON — After a surprising string of victories last fall, Democrats now face a challenging terrain as they look to hold onto their Senate majority in 2014 and prevent Republicans from gaining full control of Congress during President Obama’s final two years.
His party must defend a hefty 21 seats, including seven in largely rural states that the president lost last fall.
The task of maintaining control of the Senate has grown more daunting in recent weeks, with four Senate Democrats announcing plans to retire. Senator Carl Levin of Michigan disclosed his decision on Thursday, following Senator Tom Harkin of Iowa and Senator Jay Rockefeller of West Virginia.
Senator Frank Lautenberg of New Jersey has also said he will retire, but Democrats will be heavily favored to hold the seat. A fifth Democratic retirement could come soon from Senator Tim Johnson of Ohio, who has not yet announced his intentions.
Democrats control 55 seats in the Senate, after the November elections in which they did better than expected and gained two seats to pad their majority. That means Republicans would have to pick up six seats next year to take control for the first time since 2006.
Twenty months before the midterm elections, Republicans are laying the groundwork to try to capitalize on the defense-playing Democrats, working to recruit strong candidates in Arkansas, Alaska, Louisiana, North Carolina, South Dakota, and West Virginia — all states carried by Republican presidential nominee Mitt Romney last year.
Indeed, Republicans have only 14 of their seats up for reelection and only one — Senator Susan Collins of Maine — is in a state Obama carried last year. Just two GOP senators have said they will retire — Mike Johanns of Nebraska and Saxby Chambliss of Georgia — and they represent states that favor Republicans.
Jim Manley, a former aide to Senate majority leader Harry Reid, Democrat of Nevada, does not deny that the spate of Democratic retirements make it that much tougher to keep control in 2014. ‘‘The math is very much against Democrats,’’ he said. Even so, he adds, ‘‘The real question, however, is whether Republicans are going to keep on nominating extremists or they’re going to finally figure out that they’ve got to go mainstream.’’
At this early stage, both sides are focusing mostly on recruiting candidates — and watching for signs of how the opposition is positioning.
An early skirmish has emerged in Kentucky, where Senate Republican leader Mitch McConnell faces reelection next year. Among the Democrats talking about running: actress Ashley Judd.