WASHINGTON -- The backing of the White House, promised after his party switch, has aided Pennsylvania Sen. Arlen Specter's re-election campaign in several ways.

President Barack Obama and Vice President Joseph R. Biden have both made fundraising appearances in Pennsylvania for Mr. Specter, and the campaign has at its disposal the legions of Organizing for America, the grass-roots arm of the Democratic National Committee.

Mr. Specter also has been able to parade Cabinet secretaries around the state. In recent months, Veterans Affairs Secretary Eric Shinseki and Housing and Urban Development Secretary Shaun Donovan both have examined their operations and met with voters in the Pittsburgh area.

But in the most critical area -- votes -- the president might not be the draw that Mr. Specter envisioned in April.

Tuesday's astonishing victory by Massachusetts Republican Scott Brown to take over the late Edward M. Kennedy's seat in the U.S. Senate appeared to underscore the public's distaste for the incumbent party, following a trend from governor's races in New Jersey and Virginia last fall.

Mr. Specter is facing a primary challenge from Rep. Joe Sestak, D-Delaware County, with Republican Pat Toomey waiting in the wings for a general election fight and polling strong.

A Rasmussen poll released yesterday showed Mr. Specter with his biggest lead yet on Mr. Sestak, 53 to 32 percent. But the primary has been a fight, and either candidate will emerge bloodied, said University of Virginia professor and politics expert Larry Sabato. Like Massachusetts, Mr. Sabato said, Pennsylvania is experiencing "a Republican tide in a blue state. It will help Toomey."

Mr. Sabato allowed that an improved economy could change Democratic prospects in November, but the party can help itself, he said, if it scales back its ambitions on health care reform. Some aspects of the plan, such as ending insurance company discrimination against policy seekers with pre-existing conditions, are popular, but polls show the plan as a whole is opposed by a majority of the public.

Mr. Specter and Mr. Sestak disagreed. Both Democrats said they didn't think the Massachusetts vote was a rejection of policies such as health care reform, but instead of how Congress has been conducting its affairs.

"What really has to change is the leadership in the Senate," Mr. Sestak said, claiming that Mr. Specter's party switch is an example of cynical politics that Americans distrust. "It wasn't a vote against the Democrats. It was a vote against Washington, D.C."

In a statement, Mr. Specter concurred that "Washington must change its ways," and said bipartisanship now will be required to address health care reform, financial reform and deficit reduction.

Capitol Hill Republicans were crowing yesterday about what the upset victory may mean for their party and its chances in this year's midterm elections. Sen. John Cornyn, R-Texas, chairman of the National Republican Senatorial Campaign Committee, said he won't set a number, but "I think we will pick up a number of seats."

Mr. Cornyn's committee yesterday issued a memo discussing Mr. Brown's victory that listed Pennsylvania among five states that Mr. Obama won in 2008 where Republican chances appear to be good in the fall.

Mr. Toomey, who is considered a heavy favorite in a GOP primary against conservative activist Peg Luksik, yesterday said the Massachusetts race is a continuation of momentum he and his party have been feeling for some time. He said voters are "rejecting the ultra-liberal agenda" pushed by Mr. Obama and congressional Democrats on matters including health care reform -- which dominated Congress' attention for the second half of the year, despite not being a top priority for many voters.

"The overwhelming consensus among Pennsylvania voters in my experience is they want the federal government focused on how to grow the economy and how to keep us safe," Mr. Toomey said. "Those are the two big priorities."

There are signs that Democrats recognize that and -- once they figure out what to do about their health care initiative, a question that remained unresolved yesterday -- will pursue a jobs-heavy agenda.

Sen. Bob Casey, D-Pa., yesterday said the lesson from Massachusetts is a need to push through another jobs package, after the House passed a $154 billion measure in December. He is proposing a tax credit for companies that create jobs, a bill that he hopes will be worked into a comprehensive proposal to reduce the nation's 10 percent unemployment. "That has to be our focus, regardless of what the political environment is on everything else," Mr. Casey said.

White House senior adviser David Axelrod pushed a similar theme. He said Mr. Obama, who marked the one-year anniversary of his inauguration yesterday, will do a great deal of traveling this year to promote his economic agenda and listen to Americans.

The Obama agenda will focus on the middle class, and Mr. Axelrod acknowledged that it will be a tough sell. "It's a tough environment for the incumbent party -- I'm not going to be Pollyannaish about that; we all recognize that," he said.

"[But] people are going to care less about party and ideology than who's working for them, ... the party that's standing with the middle class, fighting for economic policies that work for most Americans and not just a few, standing up against powerful interests. That's an argument that can prevail throughout the country."

It will be tested in Pennsylvania. Specter campaign manager Chris Nicholas said the campaign is tapping into Organizing for America to recreate the networks from the Obama campaign.

Also the senator's campaign so far has raised significantly more than its adversaries -- as of Sept. 30, Mr. Specter had $8.71 million in the bank -- with help from Mr. Obama, Mr. Biden and the White House's network of donors.

If Mr. Obama wants to hold a campaign rally on Mr. Specter's behalf between now and November, Mr. Nicholas said he'd be more than happy to accept. But recent results show that it might not be any help.

"It's Pennsylvania -- I think Obama is still relatively popular," Mr. Sabato said. "But as Obama proved in Massachusetts, New Jersey and Virginia, he can't swing an election unless he's on the ballot."

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