In just a few weeks, the Republican primary season begins with at least six incumbent senators facing Tea Party challengers. The November elections are months away but these are the races to watch. At stake is whether the GOP has a real chance at taking control of the U.S. Senate this fall.

Republicans need to win six seats to take control of the chamber. Their chances could depend entirely on the candidates they nominate in primaries over the next several months.

In the last two election cycles, flawed nominees almost certainly cost the GOP victories in Colorado, Delaware, Nevada, Missouri, and Indiana.

The good news for Republicans is that these races aren’t taking place in swing states. The eventual nominees, however flawed, may still have a good chance at winning in the general election.

The bad news for Republicans is that Democrats do have a chance in at least two of the states: Georgia and Kentucky. And Democrats are still recruiting in Kansas and Mississippi with the hope they can find viable candidates for the general election.

Here are the primaries featuring Tea Party challenges:

March 4 - Sen. John Cornyn vs. Steve Stockman in Texas

May 20 - Sen. Mitch McConnell vs. Matt Bevin in Kentucky

May 20 - A four-candidate primary to replace retiring Sen. Saxby Chambliss in Georgia

June 3 - Sen. Thad Cochran vs. Chris McDaniel in Mississippi

June 10 - Sen. Lindsey Graham vs. a crowded field in South Carolina

August 5 - Sen. Pat Roberts vs. Milton Wolf in Kansas

August 7 - Sen. Lamar Alexander vs. Joe Carr in Tennessee

First Read has some analysis: "Mississippi’s Cochran is seen as the most vulnerable, while Cornyn is probably the safest; McConnell is the most high profile (and has a tough general election fight); the rules in South Carolina might make Lindsey Graham more vulnerable than he should be because if he doesn’t get 50 percent in the primary, he’s forced into a runoff; and Pat Roberts’ challenger, Milton Wolf (a distant Obama cousin on his mom’s side), has been hammering Roberts for residing in Virginia, not Kansas. Compounding Roberts’ issues is the fact that his primary is in August, a notoriously low-turnout time of year."