A federal judge in Las Vegas dismissed charges against Cliven Bundy and his sons, Ammon and Ryan, on Monday.

Judge Gloria M. Navarro of Federal District Court, in a ruling from the bench, said that the government’s missteps in withholding evidence against the three Bundy family members and a supporter, Ryan W. Payne, were so grave that the indictment against them would be dismissed.

The decision could be appealed by prosecutors. But they would only be able to bring charges again if they won the appeal and the ruling was reversed — and they then got a new indictment from a new grand jury.

Judge Navarro declared a mistrial last month in the case, stemming from an armed standoff at the Bundy ranch in 2014 that had arisen over land-grazing fees. She said then that prosecutors had erred in failing to turn over important evidence to the defense, including video taken surreptitiously within the ranch during the standoff, and evidence that F.B.I. agents were involved in the incident.