HARRISBURG -- Officially, Vince Fumo is the third-ranking leader of the state Senate's virtually powerless minority party.

Unofficially, the Philadelphia Democrat is one of Harrisburg's most influential politicians.

Dubbed by some "Prince Vince," Mr. Fumo is unlikely to be shaken off his throne anytime soon, insiders say, despite an FBI investigation into whether he extorted contributions to a Philadelphia charity that were later used to benefit him personally and politically.

Two computer technicians in the senator's office were charged Wednesday with obstructing justice by purging government computers of all traces of e-mail messages thought to be pertinent to the investigation.

The U.S. Department of Justice says more charges and more arrests are possible, but insiders and pundits predict Mr. Fumo will emerge unscathed.

"I'd be the last person to write him off," said Christopher Borick, associate professor of political science at Muhlenberg College in Allentown. "He's a true political survivor."

He will do more than survive, Dr. Borick predicted. He will continue to shape public policy through upfront demands, back-door deals and top-down pressure.

"There's formal power and then there's informal power. Formal power comes with your title, but informal power is based on the power to persuade. Some people just have that innately," Dr. Borick said.

Count Mr. Fumo among them.

He's a member of the minority party, yet he's a power broker.

He has been able to make a career out of leveraging that informal power, Dr. Borick said.

That is obvious to Marc Stier, too. Dr. Stier, a political scientist and director of the Intellectual Heritage Program at Temple University, also is an activist who frequently calls upon lawmakers.

"I call some senators and say, 'Would you sponsor this bill?' and they say, 'Have you talked to Vince yet? I'm not going to support it unless Fumo supports it. Run it by Vince and if it's OK with him then that would be fine,'" Dr. Stier said.

Fellow senators might dispute the notion that they take orders from him, but they are certainly swayed by his arguments, said Thomas Baldino, professor of social science and communications at Wilkes College in Wilkes-Barre.

The rank-and-file defer to Mr. Fumo because, they say, he is smart, bold, outspoken and thoughtful.

It doesn't hurt that he controls a big pot of money, either. As minority appropriations chairman he has a big say in where state dollars go.

"They divvy up the money and they have to keep people satisfied, but they don't have to keep everyone satisfied. They can cut people out, and senators know that," Dr. Stier said.

Mr. Fumo's intelligence, personality, persistence and tenacity allow him to get things done, supporters say.

Mr. Fumo was the driving force behind legislation that legalized slots casinos in Pennsylvania. Passage required a decade of talks aimed at securing support from the Republican majority, which had religious and philosophical qualms about gambling.

Even political adversaries acknowledge his ability to attract loyal followers and to lead them wherever he wants.

"What Fumo wants, Fumo gets. He has a total network of folks who are loyal to him because he is loyal to them," said Philadelphian Anne Dicker, who last month ran for state House against Fumo ally Terry Graboyes. Both lost to Michael O'Brien.

In some circles, Mr. Fumo is better known for quashing candidacies and projects he doesn't like than for rounding up support for new initiatives. In the late 1990s, for example, he helped thwart the Phillies' plans to build a new ballpark eight blocks from his house.

An anti-gun-control Democrat, Mr. Fumo also supported legislation that prevented Philadelphia from enacting local gun-control laws.

"He's actually more of an obstructionist than a constructionist and he's done very well at it," said Larry Ceisler, a Philadelphia public relations executive who has worked on campaigns with Mr. Fumo, but now is aligned with a rival Democratic faction in Philadelphia.

"The time I've worked with him has been the most fun I've ever had in politics. He knows how to get things done and he's a really smart guy who can see around the curves," Mr. Ceisler said.

The FBI investigation is focused on the Citizens' Alliance for Better Neighborhoods and whether the charity spent donated funds to benefit Mr. Fumo personally and politically.

Despite the computer purges, the FBI was able to retrieve several key messages that, an affidavit says, show charity money was spent on political polls and on programs that would help garner support for politicians Mr. Fumo backed. In one case, according to court documents, the senator directed an aide to use the charity's funds to buy Philadelphia a new police surveillance van and then make it look as if the vehicle had been donated by a public official who needed good publicity.

The trick now for Mr. Fumo will be avoiding the legal traps being laid out by federal investigators who arrested the two Fumo staffers Wednesday. Attorneys for the men say the arrests were an FBI tactic to get the staffers to cooperate in the investigation. Instead, the men plan to fight the charges and remain loyal to Mr. Fumo, their lawyers told reporters.

With that kind of loyalty, "Vince the Prince" could well keep his place in the castle that is the state Capitol.