NEW YORK — The former state Senate leader and his son were convicted Friday of federal extortion charges, the second time in a month that one of New York’s most powerful politicians was run out of office by a prosecution that put the capital’s political culture on trial.

The case against Republican Dean Skelos, 67, and his 33-year-old son, Adam, cast a harsh light on politics-as-usual in Albany, much like the one against former Democratic Assembly Speaker Sheldon Silver, who was convicted of bribery on Nov. 30.

“The swift convictions of Sheldon Silver and Dean Skelos beg an important question — how many prosecutions will it take before Albany gives the people of New York the honest government they deserve?” U.S. Attorney Preet Bharara said in a statement.

The convictions “should be a wake-up call for the legislature and it must stop standing in the way of needed reforms,” said Gov. Andrew Cuomo.

The government had accused the elder Skelos of strong-arming three companies with a stake in state legislation — a major real estate developer, an environmental technology company and a medical malpractice insurer — into giving work to a son prosecutors portrayed as an underachieving only child whose sense of entitlement knew no bounds.

The government said the businesses provided the younger Skelos with about $300,000 and other benefits. The scheme unraveled when investigators began recording phone calls between the father and son, prosecutors said.

Dean and Adam Skelos declined to comment as they walked away from the courthouse, with Dean Skelosresting his hand on his son’s shoulder.

The senator’s lawyer, G. Robert Gage, said: “We are obviously very disappointed with the verdict.” He said they intended to “vigorously” pursue post-trial court motions.

The verdict came after about eight hours of deliberations. As it was read, Skelos put his hand on his son’s shoulder while the senator’s second wife, Gail, wept.

The jury forewoman, Cynthia Nehlsen, said outside court: “We wanted to give them a fair trial and we did.” Sentencing was scheduled for March 3.

In closing arguments, Assistant U.S. Attorney Jason Masimore drew an analogy to Shel Silverstein’s poem “Gorilla,” about a boy who discovers he can get away with anything when he brings his giant pet gorilla to school.

“Did Adam deserve these things, earn these things? No,” the prosecutor said. “They didn’t want Sen.Skelos to unleash this gorilla.”

The defense had argued that the tapes and other evidence showed only that Dean Skelos was looking out for his son like any loving father, and that prosecutors were overreaching.

“Senator Skelos did not sell his office,” Gage the senator’s lawyer, G. Robert Gage, said in his closing. “You can be a state senator, and you can be a father.”

Gage argued that prosecutors offered no evidence proving Skelos changed long-standing positions on legislation so he could reward the businesses that employed Adam Skelos.

At trial, prosecutors used the tapes to try to demonstrate that the father and son had a blatant disregard for conflicts of interest that rose to felony crimes, and that they were aware they could get caught. In one tape, Skelos could be heard advising his son about the need for discretion amid the state capital’s ongoing corruption scandal, saying, “Right now we’re in dangerous times, Adam.”

The exchange was further evidence of a father-son conspiracy that threatened to erode the public’s faith in honest government, Masimore said.

The prosecutor cited evidence that Dean Skelos in January confronted the Nassau County executive about money the county owed to a company that hired Adam Skelos as a consultant. The senator later called his son to tell him, “All claims that are in will be taken care of,” using code language to try to cover his tracks.

Last week, Anthony Bonomo, the chief executive of the insurance company, testified that he put AdamSkelos in a $78,000-a-year position but that the son rarely reported for work. Bonomo claimed he was under pressure by the elder Skelos to keep his son on the payroll, even after Adam Skelos threatened to smash in a supervisor’s head.

The defense countered by arguing that Bonomo and others who independently decided to help AdamSkelos because they believed employing the son of an Albany power-broker would make them more money. They also attacked his and other witnesses’ credibility by accusing them of falsely portraying themselves as victims to avoid being prosecuted themselves.