Is The Tea Party Keeping Republicans in the Minority in the Senate?

Indiana Senator, Republican Richard Lugar has charged that the Tea Party has kept Republicans from gaining control of the Senate.  He says that people need to support the establishment candidates if they want to take control.

Interestingly enough, Mr. Lugar is running for reelection in 2012 and has a Tea Party challenger in his race for his seat.

Do you think that this is true?