Robin Rombach, Post-Gazette U.S. Sen. Rick Santorum concedes his race to Democrat Bob Casey last night. Click photo for larger image.

After months of tireless politicking, the strain of a difficult campaign season finally showed itself among Santorum loyalists at the Omni William Penn Hotel last night.

"I held out hope until the very end," said Liz Manganaro, 19, a student at Community College of Allegheny County and a volunteer for the Santorum campaign. "I know what a good man he is and what he was doing was changing our country for the better."

Tears streamed down her cheeks as she spoke.

Even as Sen. Rick Santorum expressed praise for his victorious opponent, Democrat Bob Casey, the Republican's supporters, gathered at the Omni William Penn, Downtown, held firm that the people of Pennsylvania had made the wrong choice.

"The state of Pennsylvania has lost a tremendous resource," said Dick Johnson, 59, of Sewickley. "The country has lost a great statesman. I'm disappointed that Pennsylvanians didn't really look at the values of the candidates."

Throughout the evening, Mr. Santorum's campaign staff maintained a brave face, even as exit polls showed that the incumbent was trailing Mr. Casey by significant margins.

Robert Traynham, spokesman for the campaign, told reporters that the campaign officials didn't believe in exit polling, citing examples from the 2000 and 2004 presidential elections ,which had incorrectly predicted the results.

Of an AP report released early this evening, Mr. Traynham said, "They've gotten it wrong in the past and now prediction is that they're going to get it wrong again."

In the end, though, the predictions proved correct, and Mr. Santorum delivered his congratulations to Mr. Casey and his thanks to his supporters in the hotel's ornate ballroom.

Mr. Santorum's loss was a stinging defeat for the conservative revolution.

"In 1994, he was out to change the culture in Washington. Now, he's a defender of the institution, the leadership," said G. Terry Madonna, director of the Center for Politics and Public Affairs at Franklin & Marshall College.

At 48, the senator likely still has many political options. Although he publicly hasn't expressed any interest in the post, Mr. Santorum could be a strong candidate if he decided to try to capture the governor's mansion at the end of Ed Rendell's second term.

Also, his popularity among conservatives nationwide will remain a potent political force, argued Bill Green, a Pennsylvania political consultant and longtime Santorum supporter.

"There could be forces that would rally behind him for a run for the presidency," he said.