President Ronald Reagan called Gov. Charles S. Robb this morning to tell him that he, too, had been governor when a man was executed and that he had sympathized with Robb last night when Virginia held its first execution in 20 years.

Reagan's call, made from Air Force One, was actually one of only a handful of calls received by the governor's office in the aftermath of the electrocution of Frank J. Coppola, a convicted murderer whose death sentence was carried out at his request after a last-minute frenzy of legal activity.

Robb, who stayed secluded with top aides during the final hours of Coppola's life, called the decision not to delay the execution his "most difficult and emotionally draining" of his eight months as governor.

But the public reaction in Virginia today was muted. On the whole, sentiment seemed to favor Robb's handling of Coppola's execution, although there lingered -- particularly among lawyers -- a certain mystery as to why the state reacted with such urgency to vacate the last-minute stay granted by Judge John D. Butzner Jr. of the 4th U.S. Circuit Court of Appeals.

That stay was vacated at 10:25 p.m. by the U.S. Supreme Court after Chief Justice Warren E. Burger polled eight justices via conference phone calls, rousing some from their beds. According to most legal observers, the high court's decision in the Coppola case was made on the narrow questions of the defendant's competency to decide his own fate and not on the constitutional merits of the Virginia death penalty statute.

The Supreme Court's ruling and Robb's decision to let the execution proceed did meet with swift and angry reaction from civil liberties activists. "It is obvious that politics comes before life for the Chuck Robbs of the world," said Virginia ACLU director Chan Kendrick.

But by midmorning, the switchboard at the state Capitol had logged 13 phone calls from the public about the execution -- 12 applauding Robb and one saying the stay should have been honored. Among the callers was Rep. Dan Daniel (D-Va.), who said he wanted Robb to know he supported his decision.

Even some of Robb's critics were supportive of his decision. "To his credit, he didn't duck it," said state Sen. L. Douglas Wilder (D-Richmond). "He made it clear from the start where he was going to come down."

But one opponent of capital punishment who witnessed the execution, Del. J. Samuel Glasscock (D-Suffolk), called it "a horrible experience" the next day. "I think in some ways I'm probably more emotional about it today than I was last night," he said. "I do not want to do it again. I would not."

Attorneys for the state had anticipated a suit like the one filed Monday by one of Coppola's former attorneys and were prepared. Since Robb was on his way back from Oklahoma yesterday, the logistics were a matter of careful timing.

Robb was in the Tulsa airport between flights and learned in a call to his office from a pay phone that the execution had been stayed 15 minutes earlier. After a three-way consultation with his executive assistant, David McCloud, and Attorney General Gerald L. Baliles, Robb ordered the appeal.

The Supreme Court's decision in favor of the state was relayed to Robb by Don Gehring, deputy attorney general, about 10:20 p.m. and within a half hour the governor had in hand a telecopy of the decision. He then relayed an order to proceed with the execution.

"It was the normal legal process of pursuing an appeal as quckly as possible," said Gehring, who said the state's argument was based strictly on Coppola's mental competency and the legal standing of his former attorney to intervene in the case.

The single page order from the Supreme Court setting aside the final barrier to the execution gave no reasons for the decision. Some legal observers said yesterday that Coppola's own wish for death, his refusal to seek further appeals and that a lower court judge had declared him mentally competent, may have entered into the high court's judgment. In particular, lawyers said, the court's action may be another sign of the majority's impatience with endless appeals and a signal that executions will not be indefinitely delayed.

"The Supreme Court is telling lower courts not to reward lawyers who engage in 11th hour pyrotechnics," said Yale Kamisar, a law professor at the University of Michigan.

"I know it may look like they kind of had a hand on the switch but I don't think legally they acted in any way that was hasty," said James Moody, a public interest lawyer at the Capital Legal Foundation in Washington.

Other lawyers disagreed, saying the court could have spent at least a few days considering a decision that meant a man's life. "It's a bloody outrage what they did and the speed in which they did it," said Alan Dershowitz, a law professor at Harvard.

But the state of Virginia argued to the justices that in the four years since Coppola was convicted and sentenced to death, his legal rights had been reviewed by 35 state and federal judges -- until Coppola himself accepted the sentence.