One month out, clock is already ticking for midterm voters

With less than a month to go until the 2014 midterm elections on Nov. 4, voters are already starting to head to the polls.

Early voting begins in California and Montana on Monday, and six more states will start this week. It begins in Indiana, New Mexico, Ohio and Utah on Tuesday, Illinois on Wednesday and Arizona on Thursday.

Other states are just closing their voter registration. Today is the last day to sign up to vote in Arizona, Hawaii, Georgia, Michigan, Florida, Kentucky, Indiana, Louisiana, Pennsylvania, Ohio, Tennessee, Texas and Washington.

The House is expected to remain under Republican control, but this year's midterms could have major implications for the Senate. The latest CBS News Battleground Tracker estimates that Republicans will win enough races to claim the majority with 51 seats, although Democrats or independent candidates across the country have complicated that effort by hanging on in tight races.

• Battleground Tracker: Kansas complicates Republicans' Senate path
• Republicans on their heels in several governors' races

Plus, control of the Senate might not be decided on Election Day: in Kansas, independent candidate Greg Orman could oust Republican Sen. Pat Roberts, and has said he will caucus with whichever party is in the majority - although he could end up being the tiebreaker. Additionally, there could be runoff elections in Louisiana (Sen. Mary Landrieu vs. Republican Rep. Bill Cassidy) and Georgia (Democrat Michelle Nunn vs. Republican David Perdue), if none of the candidates get more than 50 percent of the vote.

There are also gubernatorial elections in 36 states, and many Republicans who were swept into office during the 2010 Republican wave, including Florida Gov. Rick Scott, Pennsylvania Gov. Tom Corbett, and Wisconsin Gov. Scott Walker, are in jeopardy of losing their seats.