Republicans are poised to dramatically shrink the Democrats' Senate majority and further complicate President Barack Obama's agenda, even if they fall short of seizing control of the 100-member chamber.

Republicans are poised to dramatically shrink the Democrats' Senate majority and further complicate President Barack Obama's agenda, even if they fall short of seizing control of the 100-member chamber.


Republicans must pick up 10 seats to regain the majority they lost four years ago. Analysts in both parties consider that a tough task. The GOP would have to win every toss-up race, plus score upsets in California, Washington or perhaps Connecticut; Obama coasted in those states in 2008.


Republicans seem almost certain to pick up Senate seats in North Dakota and Indiana - where veteran Democrats are retiring - and in Arkansas, where two-term Sen. Blanche Lincoln consistently has trailed Republican John Boozman in polls. Obama lost Arkansas by 20 percentage points in 2008.


These races could have long-term implications because Democrats may have trouble retaking those Senate seats six years and 12 years from now.


Democrats privately acknowledge they have slim chances of winning any GOP-held seats this year, despite earlier hopes in Ohio, New Hampshire, Missouri and Kentucky. Republicans are reveling in their good fortunes.


"At the start of this election cycle, most political experts were predicting additional gains in the Senate by the Democrats," said GOP spokesman Brian Walsh.


The opposite is true now.


Leaders in both parties say four fiercely contested races could go either way: Nevada, Colorado, Illinois and Pennsylvania.


Nevada has gotten the most national attention. Senate Majority Leader Harry Reid's popularity has sagged lately, and he seemed almost doomed a year ago. But Republicans nominated tea party favorite Sharron Angle, a relative newcomer whose inexperience and libertarian views have raised eyebrows.