WASHINGTON – James C. Kopp, the anti-abortion zealot who fatally shot an Amherst physician nearly 15 years ago, lost his latest – and likely last – bid to have his convictions overturned at the U.S. Supreme Court on Monday.

Appealing a case that had been rejected by lower federal courts, Kopp asked the Supreme Court to hear his argument that he had been denied his constitutional right to fair trials because of improper legal representation.

But the justices, without comment, rejected his request.

The decision comes as no surprise, given that the high court agrees to hear only a small fraction of the thousands of such petitions that it receives every year.

The court’s decision, though, appears to end Kopp’s long and tortuous efforts to get his case retried.

Kopp fatally shot Dr. Barnett A. Slepian on Oct. 23, 1998, taking aim from behind the house through a kitchen window and striking the abortion provider in his back.

More than four years later, Kopp confessed to the shooting during an interview with The Buffalo News, saying he intended to only wound Slepian to prevent him from performing more abortions.

After Kopp waived his right to a jury trial, an Erie County judge convicted him of second-degree murder after a one-day trial in March 2003.

Kopp was later tried and convicted in federal court on related charges, and he is currently serving consecutive life sentences at the U.S. Penitentiary in Waymart, Pa.

He has been fighting his convictions on various grounds ever since, and Monday’s decision marked the second time the Supreme Court refused to hear one of his appeals.

This time, the justices rejected Kopp’s request that they hear his appeal of two federal court decisions from 2011, in which federal judges in Rochester and Buffalo dismissed his contention that he had been denied his constitutional right to a fair trial in both state and federal courts.

Kopp had argued that the attorney he chose to represent him in his state court murder trial, Bruce A. Barket, had a conflict of interest because he also represented two people accused of harboring Kopp while he was a fugitive. In fact, Barket was barred from representing Kopp in federal court for that very reason, and Kopp ended up representing himself in that 2007 trial.

Nevertheless, U.S. District Judge Michael A. Telesca, of Rochester, noted that it was Kopp himself who insisted that Barket represent him in his murder trial.

That being the case, “the court finds his contrary protestations to be so disingenuous as to suggest bad faith,” Telesca wrote.

In addition, Kopp argued that his lawyer persuaded him to grant that interview to The News.

But Telesca, acknowledging that the interview was “ill-advised,” noted that Barket was not to blame for it.

Kopp filed a separate but similar appeal of his conviction on federal charges, which U.S. District Judge Richard J. Arcara rejected in 2011.

Kopp originally appealed the Telesca and Arcara decisions to the U.S. Court of Appeals for the Second Circuit, which rejected the case in December 2011.

That didn’t stop Kopp’s current lawyer, Arthur L. Washburn Jr., of Dorset, Vt., from making one last try at the Supreme Court.

Told of the justices’ refusal to hear the case, Washburn said that he had known Kopp, now 58, for many years through the anti-abortion movement and that he had been pursuing the case on Kopp’s behalf since 2008

“I think most people would be of the opinion that this was the last opportunity” for Kopp to fight for a new trial, Washburn said.