­­­Voters in the United States took to the polls yesterday, casting ballots in mid-term elections where Republicans are poised to make gains and possibly recapture control of the US Senate in a race that could complicate President Barack Obama’s last two years in office.

Obama’s low job approval rating, partisan gridlock in Washington and a US economy that is not growing broadly enough to help many in the middle class are the major issues before voters in elections for 36 senators, 36 governors and all 435 members of the House of Representatives.

Republicans are expected to pick up seats in the US Senate, but polls show eight to 10 races are still toss-ups and it is unclear whether they can gain the six seats they need to control the 100-member chamber for the first time since the 2006 election.

The battle for control of the Senate also could extend beyond yesterday’s vote. Senate races with multiple candidates in Louisiana and Georgia, where the winner must get more than 50 per cent of the vote, could be forced into runoffs in December and January, respectively.

Seizing the Senate would give Republicans, who are expected to build on their majority in the House, control of both chambers of Congress.

That would constitute the most dramatic political shift since Obama entered the White House in early 2009 and might force the president to make more concessions to his Republican opponents than he would prefer.

The White House tried to play down the prospect of sharp changes in strategy after the election.

Obama will work with Congress on areas like trade and infrastructure where there is common ground, a White House official said.

On other issues, like climate change and immigration reform, Obama is likely to continue to take actions on his own. By the end of the year, he is expected to announce executive action to defer deportations for some undocumented immigrants.

Democratic senators are battling for re-election in tough races in Alaska, Arkansas, Louisiana and North Carolina, all states won by Republican Mitt Romney in the 2012 presidential election.

Democratic Senator Mark Udall also is in a tight race in the swing state of Colorado, and the fight to replace retiring Democratic Senator Tom Harkin in the swing state of Iowa is a toss-up.

Republicans are in tight races to retain their seats in Georgia, where Senator Saxby Chambliss is retiring, and Kansas, where independent Greg Orman is challenging Republican Senator Pat Roberts.

Republican Mitch McConnell of Kentucky, who polls show has a slight edge over Democratic challenger Allison Lundergan Grimes, would replace Democrat Harry Reid as Senate majority leader if Republicans win the Senate and he hangs on for re-election. Several governors’ races also appeared too close to call, including the Florida contest between incumbent Republican Governor Rick Scott and Democrat Charlie Crist.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.