President Biden says that the conviction of President Trump at New York reaffirmed the principle that no one is above the law, while stressing that the case was brought by the state of New York and not the federal government.

“It’s reckless, it’s dangerous, it’s irresponsible for anyone to say this was rigged just because they don’t like the verdict,” Mr. Biden said in comments Friday afternoon, adding that the criminal justice system “literally is the cornerstone of America.”

Mr. Biden was addressing a position adopted by almost every elected Republican, that the trial was illegitimate or that it was “rigged,” in the words of Trump.

“The jury heard five weeks of evidence. Five weeks, after careful deliberation, the jury reached a unanimous verdict” Mr. Biden said. “They found Donald Trump guilty on all 34 felony counts.”

Mr. Biden stressing that this was “a state case, not a federal case” also rebuked the line picked up by Trump at a morning press conference, where he claimed that Mr. Biden and the Justice Department were leading the case in New York.

“Donald Trump was given every opportunity to defend himself,” Mr. Biden said. “A state case, not a federal case, was heard by a jury of 12 citizens. Twelve Americans. Twelve people like you, like millions of Americans who served on juries.”