The mid-term election could be seen as a referendum by voters on the economy and the policies of the Obama Administration.

The Republicans benefited with candidates winning at least 10 of 13 closely contested U.S. Senate races. They took seats held by Democrats in Arkansas, Colorado, Iowa, Montana, North Carolina, South Dakota and West Virginia, and seized control of the Senate, the first time since the 2006 election.

Republicans picked up 10 more seats in the House, adding to their majority, and won more gubernatorial races in Florida, Maryland and Massachusetts. Democrats kept their New Hampshire and Virginia Senate seats.

President Obama is due to speak on the election results Wednesday afternoon.

House Speaker John Boehner said the victory is not a time for celebration for his fellow GOP.

"It's time for government to start getting results and implementing solutions to the challenges facing our country, starting with our still-struggling economy," Boehner told the Associated Press.

The election was not just about the Republican landslide. Ballot initiatives proliferated in state after state from legalizing marijuana, to minimum wage increases to conservation funding to banning fracking. 

"We knew going into this election that the electoral map was very positive for Republicans. I think also in mid-term elections the overall population turnout tends to be lower, and it also benefits Republicans. Those are two important points to keep in mind as we think about the results," said Vanessa Cardenas, Vice President of Program 2050 at the Center for American Progress Action Fund.

"Even though a lot of Republicans won their races, especially with governors, that on issues, the ballot initiatives -- the minimum wage ballot initiative in five states passed, some ballot initiatives on paid sick leave passed, the initiative on personhood in Colorado was defeated, and the ballot initiative in California on criminal justice also passed. So we have this really interesting situation where in a lot of the states where you have conservatives and these red states became even redder. At the same time, you have Americans voting on ballot initiates that progressives and Democrats have been supporting, so its two different messages. Mid-terms elections is lower turnout and voters tend to vote against the party which is in the White House, yet they are also voting for these issues that are central to the Democrats."