美国选民星期二参加选举投票。这次选举可能改变美国国会目前的权力格局，可能会对奥巴马总统的立法议程构成严重挑战。
美国各地的选民在公立学校和市政中心排队，在正常的工作日里拿出一些时间来投票。
民意调查显示，共和党即将从奥巴马的民主党手里夺回对众议院的控制权。共和党人也可能在参议院赢得几个席位。
在失业率接近10%的情况下，人们对美国经济的严重担忧对激发共和党人的活力起了推波助澜的作用。共和党全国委员会的主席斯蒂尔在竞选结束的时候表示，共和党人希望“与美国人民有一个新的开始”。
“茶党”运动的支持也推动共和党人在选举中赢得席位。茶党是一个松散，直言的组织，呼吁减税和减少政府支出。
奥巴马一直在设法鼓动民主党选民。他们在两年前以很高的投票率将奥巴马选为总统。星期二，奥巴马接受了好几家电台的采访，敦促人们投票。
Americans are voting in elections Tuesday that are likely to shift the balance of power in the U.S. Congress, posing a serious challenge to President Barack Obama's legislative agenda.
Voters across the country are lining up at public schools and civic centers, taking a few minutes to cast their ballots on a regular work day in the United States.
Polls show the Republican Party poised to take control of the House of Representatives from Mr. Obama's Democratic Party. The Republicans are likely to gain a few seats in the Senate as well.
With unemployment near 10 percent, serious concerns about the U.S. economy have helped to energize Republicans. The party's chairman, Michael Steele, said at the end of campaigning Republicans are hoping for a "fresh start with the American people."
Republicans are also gaining ground with the support of the "Tea Party" movement, a loosely organized but vocal group calling for lower taxes and less government spending.
Mr. Obama has been trying to rally Democratic voters who came out in huge numbers two years ago to elect him as president. He is taking part in a number of radio interviews Tuesday to urge people to vote.