Former New York Assembly speaker Sheldon Silver arrives at the courthouse in New York last year. Silver, who was convicted of fraud and extortion, was sentenced to 12 years in federal prison Tuesday. (Seth Wenig/AP)

Former New York State Assembly speaker Sheldon Silver was sentenced Tuesday to 12 years in prison in a federal corruption case that prosecutors said “struck at the core of democratic governance” and polluted the institution where he wielded immense power.

Silver, 72, was convicted last year of taking millions of dollars in bribes and kickbacks in exchange for various official favors. According to prosecutors, Silver, a lawyer, persuaded a doctor to pass on “valuable leads to unrepresented patients with mesothelioma,” and in return, gave the doctor state grants for research. He also took official actions to help real estate developers that gave business to a law firm that then sent Silver kickbacks, prosecutors said.

In court filings, prosecutors had asked that Silver (D) face a term “substantially in excess” of 10 years. Defense attorneys argued for a sentence of “extensive community service and little – if any – incarceration.” U.S. District Judge Valerie Caproni said in court that she was moved by the many letters written on Silver’s behalf but that the case caused “an incalculable intangible harm to the people of New York,” according to a New York Times reporter watching the proceedings.

U.S. Attorney Preet Bharara wrote on Twitter that the sentence was a “just and fitting end to Sheldon Silver’s long career of corruption.”

Silver can appeal, and his attorneys have indicated in court filings that they intend to do so. They wrote that they did not want to re-litigate the case at sentencing, but instead sought to persuade Caproni to consider a more complete portrait of Silver and to take into account his many accomplishments in government. Those included helping to rebuild Lower Manhattan after the terrorist attacks on Sept. 11, 2001, and improving education and health care in New York, they wrote.

“Mr. Silver has demonstrated a capacity to do a tremendous amount of good for the public. His personality, vision, and persistence have been brought to bear with great effect,” his attorneys wrote. “It is doubtful this Court will ever sentence a defendant with as rich a record of doing so much for others.”

In a letter to the judge, Silver did not address the specifics of his case, but he acknowledged the government had been “ridiculed” because of him.

“I have failed the people of New York,” Silver wrote. “There is no question about it.”

Prosecutors wanted Silver, who they said “repeatedly abused that position of power and public trust during the span of more than a decade for private gain,” to face a sentence greater than any other imposed on a New York state legislator for corruption offenses. They wrote that they had no quarrel with the probation office’s calculation of federal sentencing guidelines — which called for 21 years and 10 months on the low end and 27 years and three months on the high — and they felt he deserved much more than the 10 years the office recommended.

“Silver’s crimes corrupted the institution that he led for more than 20 years,” prosecutors wrote. “As a fixture in the legislative leadership, an entire generation of New York legislators served in an institution framed by his corrupt example.”

New York Governor Andrew M. Cuomo (D) said in a statement: “Today’s decision sent a simple message that officials who abuse the public’s trust will be held accountable. Justice was served.”

Prosecutors also alleged that Silver’s corrupt self-dealings extended to his personal life, asserting he had an extramarital affair with one woman who lobbied him about state business and another whom he recommended for a job, then tried to hide the relationships while giving his mistresses preferential access and treatment. Defense attorneys have called those purported affairs “unproven, salacious allegations that have no place in this case or public discussion.”

According to reports, Silver must report to prison by July 1.