HARRISBURG — A corruption scandal that has roiled the Statehouse for nearly two years reaches court today, when a powerful former House leader, a representative who was his protege and four legislative aides will appear on charges they helped divert millions of taxpayer dollars and other public resources to run campaigns.

A preliminary hearing scheduled to last several days will determine whether prosecutors have enough evidence to proceed with the trial of former House Democratic whip Mike Veon, state Rep. Sean Ramaley and the House aides, all Democrats.

The hearing will focus on six defendants. Since Friday, six other aides waived their right to a preliminary hearing.

All 12 are accused of theft, conflict of interest and conspiracy, though the number of charges and types of allegations vary.

Veon, among the Legislature's most powerful figures before losing re-election two years ago, faces the most counts, 59. Prosecutors say the former 11-term lawmaker from Beaver County diverted taxpayer funds and used state workers illegally in his role as a chief campaign strategist for the House Democrats.

In a 74-page report issued in July, a grand jury charged that taxpayer-financed bonuses were doled out as rewards for campaign activity, state-owned computers and other equipment were commandeered for political purposes and government contracts were awarded to firms to provide electioneering services.

The investigation has been headed by Republican Attorney General Tom Corbett, who has been criticized for only going after Democrats.

But Corbett has said Democratic and Republican caucuses in both the House and Senate are still being investigated, though no additional charges will be brought before Election Day.

Ramaley, a two-term representative from Beaver County, is the only sitting lawmaker currently charged. Facing six counts, he is accused of using his time as an aide to Veon in 2004 to campaign for a House seat. He is not seeking re-election and has abandoned a once-promising bid to move up to the Senate.

The 10 aides charged are all current or former House Democratic caucus employees, including Mike Manzo, formerly chief of staff to Majority Leader Bill DeWeese of Greene County. Manzo faces 47 counts, the second highest number.

The scandal began to unfold in January 2007 when The Patriot-News of Harrisburg first reported that legislative employees had been granted millions in bonuses, payments that investigators allege were sometimes illegal rewards for campaign work.