By Larry Kane

PHILADELPHIA (CBS) – The suspension of Rick Santorum’s campaign poses a real problem for the Republican establishment in Pennsylvania — one with serious consequences.

With Mitt Romney facing token opposition now, voter turnout on the Republican side might be much lighter. That means the hard fought five-candidate struggle for the US Senate nomination to oppose Bob Casey may be affected.

(KYW's Larry Kane.)

The race is the first test of Governor Corbett’s political power. Corbett and the state committee have endorsed Chester County businessman Steve Welch, who is opposed by the well financed Tom Smith of Western Pennsylvania. The polls are all over the place, with Berks County’s Sam Rohrer running well. The other candidates are Mark Scaringi and David Christian.

Smith has the financial advantage. Welch has the party. But Corbett’s political imprint is on the line.

Most surveys show 35-50 percent of voters are undecided. A smaller turnout usually helps the endorsed candidate, but this is not a usual political year.