Twenty months ago, Larry Young stood on the floor of the Maryland Senate, in chambers filled with the stately oil portraits of his predecessors, and pleaded with his 46 colleagues to save his political life and not expel him from their midst. But by a wide margin, they did, making the once powerful Baltimore Democrat the first senator thrown out of office in state history.

Tomorrow, in a courthouse just two blocks from that Senate chamber, Young will begin to plead his case again, this time to a jury. In a sleek, modern courtroom devoid of historical accouterments, jurors will decide whether Young is a criminal.

Young, 49, stands accused of demanding bribes and extorting money and favors from health care companies seeking to do business in Maryland. As a senator and, before that, as the chairman of the House Environmental Matters Committee, Young was once one of the most powerful people in the state on issues relating to health care. Before his expulsion, he already had made history when he became the first African American to become chairman of a General Assembly committee.

In December, a nine-count indictment charged Young with demanding $52,000 in bribes, a personal computer and a laptop computer from Diagnostic Health Imaging Systems and its successor company, PrimeHealth Corp. of Lanham. It charged him with extorting $72,493 and computers from the companies for himself and $8,000 for an aide who was not charged. Young also was charged with filing a false state income tax return in 1995.

PrimeHealth is one of eight companies participating in a state program to save money by directing Medicaid recipients into health maintenance organizations. It has about 12,000 clients and was taken over by state regulators last October after a state inquiry uncovered mismanagement at the company, which PrimeHealth officials have denied.

In court documents, prosecutors said Young demanded money from the company during telephone conversations the former senator conducted from his Annapolis office. The documents said Young received cash payments during meetings at the company's Lanham office.

At the height of his power, Young wielded deep political influence. He was a power broker who could draw voters to the polls and raise money. And that, in turn, made his support sought after by other politicians, including Gov. Parris N. Glendening (D), who needed his help for their campaigns.

Young was a lawmaker whose phone calls got returned. Lobbyists sought his favor and his District 44 constituents adored him. After his expulsion, in January 1998, they took to the streets in rallies to support him, declaring that Young was treated unfairly because he is black. The local Democratic organization nominated him to fill the vacancy his expulsion had created. Glendening, acting on the advice of state Attorney General J. Joseph Curran Jr. (D), declined to appoint him, filling the slot with someone else.

Since then, Young has remained a presence. He hosts a talk show on a Baltimore radio station and continues to attend conferences of black legislators. After his indictment in December, he told radio listeners: "Did I willfully commit any crime? Absolutely not."

"His spirits are very good. He's upbeat," said someone who spoke with him recently.

Young's alleged wrongdoing first came to light in a series of articles in the Baltimore Sun. The newspaper reports prompted the General Assembly's Joint Committee on Legislative Ethics to investigate Young and recommend his expulsion, which the full Senate approved, 36 to 10. The articles also prompted State Prosecutor Stephen Montanarelli, who oversees public corruption cases, to begin a grand jury investigation.

The Anne Arundel County grand jury that indicted Young heard evidence for 11 months. Among those who testified were two top officials from the state health department and Glendening's chief of staff, Major F. Riddick Jr.

During a hearing in the case last month, Montanarelli said Young met with a top-ranking state official about the same time he was demanding the bribes he is charged with soliciting. He declined to name the official.

Montanarelli has said the investigation did not target anyone in the governor's administration. Still, the close relationship Young had with Glendening and many other powerful state officials has left some Annapolis political observers wondering whether there will be any embarrassing political revelations during the trial.

"I don't think this has bombshells unless Larry Young surprises everybody and starts saying people high in government in Maryland were involved," said former House majority leader D. Bruce Poole.

Last month, Young sought to have the charges thrown out or, failing that, the trial moved to Baltimore. His attorneys argued that Young's power as a legislator originated in his district. They also hoped to find a more sympathetic jury in the majority-black city.

But Circuit Court Judge Joseph P. Manck ruled that the case belonged in Anne Arundel County because Young exercised his duties as a legislator in Annapolis. Attorneys in the case said they expect the trial to last at least two weeks.