A widening criminal investigation accuses some of Pennsylvania's most powerful state lawmakers of illegally converting the public work force and the Legislature's thick bankroll into potent re-election tools.

The attorney general's three-year-old probe has already resulted in 25 arrests, the most recent coming last week, when the third-ranking Democrat in the state House and a member of the governor's cabinet were charged.

It was not long ago that defendants John Perzel, Bill DeWeese, Mike Veon, Brett Feese and Steve Stetler would have been at or near the top of any list of Pennsylvania's most powerful political figures.

Perzel, a Philadelphia Republican, was speaker of the House, while DeWeese and Veon, both from western Pennsylvania, held the two highest ranking positions in the House Democratic caucus.

As recently as four years ago, the three men's fingerprints would have been on virtually any significant deal in Harrisburg, while Feese, a Republican from Lycoming County, and Stetler, a York Democrat, oversaw their respective caucus' campaign efforts.

Attorney General Tom Corbett, a Republican who hopes to become governor-elect in 2010, has been on a crusade to stamp out what he portrays as a corrupt culture that has systematically siphoned off taxpayer-paid employees and equipment intended for General Assembly work.

The diversion of public employees for campaigning has surfaced repeatedly in recent years at state Capitols across the country, including Florida, Minnesota, Missouri and South Carolina.

In Wisconsin, a caucus scandal resulted in the criminal convictions of five high-ranking lawmakers, and just last week a Hawaii state representative agreed to pay a fine to settle a complaint she violated a state law that prohibits legislators from using state time, equipment or facilities for campaigning.

In Pennsylvania, it is illegal for anyone to gain private monetary advantage from holding public office, and the charges involved in the investigation so far have included theft, obstruction, conflict of interest and conspiracy.

Corbett's public corruption unit has hauled dozens _ if not hundreds _ of people before secret grand juries, seized boxes of material from state Capitol offices, pored over mountains of e-mails and other records and provided immunity to an undisclosed number of witnesses.

But state prosecutors have lost the only case to have gone to trial so far, and Corbett's gubernatorial ambitions may rise or fall on the results of the most important trial _ the one involving Veon that is set to begin in a Harrisburg courtroom next month.