The Republican Party regained control of the House of Representatives in Tuesday's mid-term elections, but they fell short of a majority in the Senate, despite significant gains there.

The Republicans took five seats currently held by the Democrats, in Arkansas, Indiana, Wisconsin, Pennsylvania and North Dakota.

The GOP made major inroads in the House, with a gain of at least 50 seats there as of late Tuesday night.

Several Tea Party candidates won Senate seats for the Republicans, including Rand Paul in Kentucky and Marco Rubio in Florida.

However, Christine O'Donnell, a Tea Party favourite whose strange comments made her a national icon, lost in the Delaware race. O'Donnell beat a candidate in the Republican primary who was expected to win the seat long-held by Vice-President Joe Biden.

There were 37 Senate seats up for grabs Tuesday -- 19 held by Democrats and 18 by Republicans, and 435 seats in the House of Representatives.

Republicans needed 40 more seats to win the House, and early results show they have exceeded that number. They needed to gain 10 seats in the Senate.

Political pundits nearly unanimously expected this to be a bad day for U.S. President Barack Obama, in a vote that has become seen as a referendum on his first two years in office.

Mark Plotkin, a U.S. political analyst, said the Republican Party was poised to gain, but only by default.

"These votes against the Democrats are not pro-Republican. They hold Republicans in the same minimum high regard," Plotkin told CTV News Channel. "It is really retaliation against who is in power. It is not that they think Republicans are the saviours. They just want to send a message."

Plotkin said Obama, who came in to power on a call for change, lost his halo when he pushed the "laudable" health care bill to the top of his priority list, instead of fixing the mess he had inherited.

"While this was going on, I think people felt this was a misplacement of priorities. We had an economic tsunami, we had terrible unemployment, we had terrible economic anxiety and he didn't seem to be sensitive to that. All he was doing was working on the health care bill," Plotkin said.

Obama argues the health care reform and $800 billion he poured into the economy saved the country from falling into a new Great Depression.

Anger, not hope, leads election

Americans are angry about the state of the economy and record high unemployment, and are likely to take out their frustrations on Obama and his party.

"President Obama came to power on this promise of hope and change and most voters in America are saying 'OK, where's the hope, where's the change?'" said CTV's Joy Malbon, from Washington.

A significant setback in the midterm elections would make it difficult, if not impossible, for Obama to carry out his agenda in the next two years of his term, likely putting government in a state of deadlock.

Plotkin said political gridlock could occur if the Republican Party reclaims majority of the House of Representatives.

But he expects Republicans learned a lesson in 1994, when Democrats lost 50 seats in the House of Representatives but still managed to get Bill Clinton re-elected two years later.

Plotkin said Republicans "over-acted" after that win, allowing momentum to swing back to the Democrats.

He added that once they secure a more active role in government, they could face a similar backlash if the public thinks their focus is solely on knocking Obama out of the White House.

Motivating last-minute support

Obama was on a whirlwind last-minute tour on the weekend, visiting supporters in four states and calling on them to get the vote out.

"If everyone who fought for change in 2008 shows up to vote in 2010, we will win this election, I am confident of that," he said.

Obama and other Democrats have been desperate to motivate their supporters to show up at the polls. By contrast, Republican voters seem energized and are expected to make a strong showing at the polls.

In recent months Republicans have bounced back from a crippling loss in 2008 that saw Obama and the Democrats carried into the White House.

The Tea Party, a grassroots conservative movement, has been a major part of that groundswell, Malbon said. Twenty-eight million Americans now affiliate themselves with the group despite the fact it has no manifesto and no central governing organization.

"These are people saying we're mad as hell at Washington, we're not going to take it anymore -- no more taxes and we want smaller government. And this is really driving this energy, driving the Republicans and they're fired up and they're ready to go," Malbon said.

A total of 160 ballot questions will also be decided in 37 states on Tuesday -- 42 of them initiated by citizens.

Among the issues is a proposal to legalize recreational marijuana use in California. South Dakota and Arizona will consider legalizing medical marijuana use, and Oregonians will vote on whether a medical marijuana supply system should be set up.

Colorado will look at when a fetus should be considered a person, and therefore be subject to the state's bill of rights.

The implementation of new health care laws will also be on the ballot in several states.

Democracy from space

Meantime, three Americans cast their ballots from space. The U.S. astronauts on board the International Space Station voted from more than 320 kilometres above the planet.

Scott Kelly voted Sunday, while Douglas Wheelock and Shannon Walker cast their ballots through a secure email system on Tuesday.

They called it an "honour and a privilege" to vote from space.