The New York State Bar Association on Monday condemned President Donald Trump's commutation of the prison sentence of his longtime ally Roger Stone, calling it a "perversion of justice, plain and simple."

Trump on Friday commuted Stone's 40-month sentence, handed down over his conviction on charges stemming from Special Counsel Robert Mueller III's investigation, days before Stone was set to report to prison. The White House, in announcing the grant of clemency, attacked the Mueller probe, and Mueller made a rare public statement Saturday, defending his team in a Washington Post op-ed.

On Monday, New York State Bar Association President Scott M. Karson said in a statement that is it "inexcusable for a president to use his power to commute sentences to save a political crony who was convicted by a jury of his peers of lying to protect the president."

"This power is supposed to be used to correct injustice and safeguard the nation and not to benefit friends and allies," Karson said.

A federal jury in Washington, D.C., last year found Stone guilty on all charges brought against him by Mueller, including lying to the House Intelligence Committee as part of its Russia probe and witness tampering.

The act of clemency has sparked outrage particularly among Democrats in Congress, with Speaker Nancy Pelosi calling for legislation "to ensure that no president can pardon or commute the sentence of an individual who is engaged in a cover-up campaign to shield that President from criminal prosecution." However, scholars are doubtful that any meaningful limits can be lawfully placed on the broad pardon powers established in the Constitution.