Republican U.S. Senate candidate and Speaker of the North Carolina House of Representatives Thom Tillis (2nd R) greets voters during a Davie County GOP rally November 2, 2014 in Mocksville, North Carolina. Incumbent Sen. Kay Hagan (D-NC) is facing challenge from Tillis for her seat in the U.S. Senate. Image Credit: AFP

Washington: Republicans are expected to take control of the US Senate and strengthen their majority in the US House of Representatives in midterm elections on Tuesday, deepening the long-running political gridlock in Washington.

Buoyed by recent polls and predictions, Republicans exuded confidence on the eve of the election.

“I think the wind is at our back,” Kentucky Senator Rand Paul said on CNN’s ‘State of the Union’.

Republicans need to gain six seats to take control of the Senate, which has been in the hands of US President Barack Obama’s Democratic Party.

While most polls predict a favourable result for the Republican Party — The Upshot, a New York Times website for politics, for example, predicts Republicans have a 70 per cent chance of winning a majority in the Senate — the outcome of the vote may be decided by the large number of undecided voters.

Republicans are expected to easily win Senate elections in South Dakota, Montana and West Virginia. They are especially confident of picking up a Senate seat in Iowa where the Republican candidate, Iraq war veteran Joni Ernst, leads Democrat Bruce Braley. Senate Majority Leader Harry Reid admitted over the weekend that a Republican victory in Iowa would cost him his Senate job.

Democrats are anxiously watching the Senate elections in Alaska, Arkansas, Colorado, New Hampshire and North Carolina, where Democratic incumbents are locked in tough battles.

Yet some Republican senators themselves are facing stiff competition. In Georgia, Democrat Michelle Nunn is in a neck-and-neck race with Republican David Perdue, while in Kansas Republican Senator Pat Roberts is struggling to fend of a challenge from independent Greg Orman.

Both major political parties — Democratic and Republican — have poured significant amounts of money into this election making it the most expensive midterms in US history. The Centre for Responsive Politics says almost $4 billion will be spent on campaigns with Republicans outspending Democrats. The Senate battle in North Carolina between Democrat Kay Hagan and Republican Thom Tillis is the most expensive with $113 million spent so far.

While political pundits have been focused on prognosticating the future of the Senate, in the House of Representatives, where all 435 seats are up for grabs, the only question is: By how many seats will the Republican Party grow its majority? The Democratic Party lost its majority in the House of Representatives in 2010.

The US Congress has been one of the least productive in recent history. A Pew Research Centre poll in July found 69 per cent of Americans had an unfavourable opinion of Congress, yet 48 per cent of registered voters said they’d like to see their own representative win a new term.

Unsurprisingly then most incumbents in the House of Representatives are likely to keep their seats. “Few things in life are more predictable than the chances of an incumbent member of the US House of Representatives winning re-election,” says the Centre for Responsive Politics.

Even though American voters have a more positive outlook on the economy than in the previous two election cycles, a majority of them are dissatisfied with the direction in which the country is going and a recent Pew Research Centre poll found Obama’s approval ratings have slipped to 43 per cent.

Republicans have characterised Tuesday’s election as a referendum on Obama.

“This is really the last chance for America to pass judgement on the Obama administration and its policies,” former Republican presidential nominee Mitt Romney said on ‘Fox News Sunday’.

This is the reason why most Democratic candidates have chosen to keep their distance from Obama even as they have readily embraced a more popular Democratic brand: the Clintons.

Former President Bill Clinton and his wife and former Secretary of State, Hillary Rodham Clinton, have criss-crossed the country campaigning for Democratic candidates. Hillary Clinton is widely expected to enter the race for the presidency in 2016.

“A midterm election almost always produces losses for the president’s party in congressional and state elections,” Thomas Mann, a congressional scholar wrote in a blog for the Brookings Institution.

“Those losses are magnified when, as is the case this year, the president’s approval rating is closer to 40 than 50 per cent and the public feels pessimistic about the state of the economy and the future of the country,” he added.

Despite the fact that the Republican Party is poised to pick up more seats the party isn’t winning any popularity contests anytime soon. A Pew Research Centre survey found that while Americans’ views on the Democrats are evenly split, only 38 per cent have a favourable view of the Republicans.

Democrats are putting their faith in such polls. They used the Sunday shows talk shows to make the case that early voting numbers — which typically favour Democrats who come out in fewer numbers on Election Day — suggest they’ll hold onto some seats.

“I think we’re going to hold the Senate, and the reason that we’re going to hold the Senate … is because we have a ground game,” Debbie Wasserman Schultz, chairwoman of the Democratic National Committee, said on ABC’s ‘This Week’.

So what would a Republican-controlled Congress mean for the last two years of Obama’s presidency?

“Obama’s legislative priorities will continue to be ignored or defeated in Congress as they have since 2011,” Mann writes. “To be sure, a Republican Senate would make life even more difficult for the President.”