"Republicans are not sure yet they can beat Obama, so they're focusing on the Senate," said Republican strategist and CivicForumPAC chairman Ford O'Connell. Last year his PAC supported the successful campaigns of Florida Governor Marco Rubio and Pennsylvania Rep. Pat Toomey.

Now, in states such as Michigan, Wisconsin and Pennsylvania, conservative donors are waiting to see if Tea Party groups can coordinate their efforts, O'Connell said.

"If they can unify behind viable candidates, more money will flow to those candidates," O'Connell said. "The big question is, can they get there?"