Conservative former congressman Pat Toomey made it official yesterday, signing on for a rematch with moderate Pennsylvania Sen. Arlen Specter in the 2010 Republican Senate primary.

Starting with a talk-radio interview in Allentown and a video on his new campaign Web site, Toomey said he was running to stop the "bailouts and the spending stampede" and because Specter had consistently supported "increased government spending and a liberal agenda on social, labor, immigration and national security policies."

In 2004, Toomey shocked politicos when he came within 17,000 votes - out of 1 million cast - of defeating Specter, despite being outspent, 4-1. This time, he won't have the element of surprise; Specter, anticipating his challenge, has already aired commercials attacking Toomey's record.

The announcement came on tax-filing day, as conservative activists across the country held "tea parties" to protest what they see as out-of-control government spending that will lead to unsustainable debt and higher taxes.

Toomey, 47, had been exploring a run for governor until an eruption of anger in the GOP's conservative base greeted Specter's crucial vote in February for the Democrats' $787 billion economic stimulus bill. Two recent independent polls found that a narrow majority of Republicans surveyed favored someone new in the Senate seat.

Specter's campaign said in a statement that Toomey was too far to the right to win a general election in Pennsylvania, a state dominated by centrist voters that has been trending Democratic in recent years.

After all, the statement said, Toomey is in some ways more conservative than former Sen. Rick Santorum (R., Pa.), who lost his 2006 reelection bid by 18 percentage points.

"Without Sen. Specter's seat, which Mr. Toomey would certainly lose, there would no longer be 41 Republican senators to filibuster and stop the Democrats from passing card check, raising taxes, and implementing President Obama's massive spending plans," said Christopher Nicholas, Specter's campaign manager.

Specter recently voted against Obama's proposed 2010 budget and announced he would oppose the so-called card-check bill that would make it easier for unions to organize. Toomey said those were politically motivated flip-flops.

Though Specter, 79, who is seeking his sixth term, has proved a popular vote-getter with Democrats and independents in general elections, the primary could be his biggest challenge, with a smaller and more conservative Republican electorate.

Registered Democrats outnumber Republicans by 1.2 million, up from 550,000 three years ago. A February poll of GOP switchers, conducted by Muhlenberg College, found that most were moderates turned off by the Republican Party's rightward drift.

Specter's geographic base, Philadelphia and its four suburban counties, has 83,412 fewer registered Republicans than in 2004. In Pennsylvania's closed primary system, only voters registered with the GOP may participate in the May 19, 2010, primary.

"Specter's vulnerability from the right was thoroughly exposed five years ago and he's even more vulnerable today," said Bill Green, a Pittsburgh-based political analyst. "A lot of moderate Republicans have become Democrats."

Toomey said yesterday that the Santorum analogy did not fit because 2006 was driven by voter backlash against the GOP over the Iraq war and corruption scandals - "the worst year for Republicans since 1974, right after Watergate."

From 1999 to 2005, Toomey represented the 15th Congressional District, which is centered in the Lehigh Valley but also includes eight municipalities in northern Montgomery County. He said his ability to win in the Democratic-leaning district proves his appeal.

"The extent of the animosity to Sen. Specter is so broad and so intense that if he were to win this primary, he would ensure a third-party conservative candidate," Toomey said.

Analysts say they expect the contest to be one of the nation's most expensive and negative Senate races next year. Two weeks ago, Specter launched a TV ad linking Toomey to the financial crisis because of his past as a derivatives trader on Wall Street and his aggressive advocacy in Congress of deregulation.

After leaving Capitol Hill, Toomey served as president of the fiscally conservative Club for Growth in Washington until he resigned Monday. He worked on Wall Street from 1984 to 1990, then started a chain of restaurants with his brothers.

Specter had to tweak his ad because it accused Toomey of selling "credit-default swaps," a derivative backed by home mortgages blamed for triggering the near-collapse of the banking system. It turned out those instruments had not been invented when Toomey worked on Wall Street; he sold derivatives tied to interest rates and foreign currency.

But the Specter campaign insisted that Toomey's ties to Wall Street proved he was out of touch with voters' concerns. It later publicized that Toomey's online biography had been changed to remove the word derivatives.

"I don't think there's anybody alive who thinks that the interest-rate and currency swaps of the 1990s had anything to do with the banking crisis of 2007," Toomey said. "Sen. Specter is a very talented politician, but duplicity always catches up with you."

Specter raised $1.3 million in the first three months of the year and had $6.7 million in the bank as of March 31, according to the federal campaign-finance report he filed yesterday.

Toomey, who raised and spent about $4 million in 2004, said he was confident he could raise several times that now, given his national fund-raising base from heading the Club for Growth and the polling that shows Specter in trouble.

He may not be alone in challenging Specter. Conservative activist Peg Luksik of Johnstown, who ran for governor three times in the 1990s, is also in the race.

Luksik said yesterday that she was in the GOP primary to win.

"I'm closer to the voters than both Mr. Toomey and Mr. Specter, who have lived and breathed Washington for the last five years while I've lived and breathed Pennsylvania," Luksik said. "It makes a difference in your perspective."

On the Democratic side, former National Constitution Center chief executive Joe Torsella is the only announced Senate candidate. He has raised just under $600,000. State Rep. Josh Shapiro of Montgomery County also is considering the race.

"We are looking at a range of candidates," Sen. Robert Menendez (D., N.J.), chairman of the party's Senate campaign arm, said Monday. "If we get a good candidate, I think that there is a good opportunity."

Menendez said the Republican fight "creates a debilitating process for the general election."

Toomey, however, pointed to the success of the tea-party protests.

"They were entirely spontaneous, not rent-a-crowds," he said. "It shows what side the energy is on."

Contact staff writer Thomas Fitzgerald at 215-854-2718 or tfitzgerald@phillynews.com.
Staff writer Jonathan Tamari contributed to this article.