Fox News contributor Michael Barone joined Martha MacCallum to offer his expertise on how the U.S. Senate will look after Election Day. Currently, Democrats hold a 53-vote majority in the Senate.

Barone said it's still very much up for grabs, pointing out that either party could make gains on Tuesday. Two races that will factor heavily into the equation are in Wisconsin

and Nebraska, where Democrats Herb Kohl and Ben Nelson are retiring.

Barone said in Nebraska, Republican Deb Fischer will have an advantage over Bob Kerrey because the state is going to go heavily for Romney.

In Wisconsin, former governor Tommy Thompson is locked in a virtual tie with Democrat Rep. Tammy Baldwin.

Check out Barone's full analysis: