If it was a terrible swift sword, NBC brought it down more swiftly than the other two networks. At 8:15 last night, NBC News was first to declare an end to the Carter administration and to project Ronald Reagan as the 40th president of the United States.

That was with only 5 percent of the vote counted, but NBC News had done some gun-jumping even earlier. John Chancellor began the NBC Nightly News by saying that according to an NBC-Associated Press poll, "Ronald Reagan appears to be headed for a substantial victory." On the CBS evening news, Walter Cronkite said, "The smell of victory is in the air for Ronald Reagan," and on ABC's World News Tonight, Frank Reynolds said cautiously, "It appears that" Reagan was ahead.

NBC News had the itchiest trigger finger when it came to projecting winners. As of 8:30, NBC had called 18 states, ABC 11, and CBS only 9. ABC's Ted Koppel seemed to be responding to the NBC runaway when he explained to viewers that ABC wouldn't call any state until the polls had closed there. NBC was making its projections on the basis of exit polls conducted at voting sites.

Everyone seemed a bit surprised at the strength and tenacity of Reagan's lead, which sent the network news departments bursting out of their starting gates earlier in the evening than they may have expected. On ABC shortly after 7 p.m., Sander Vanocur reported from Democratic headquarters, "You can't sense any mood of great gaiety in this room right now." A few minutes later, Cronkite was reporting "An early Reagan lead tonight in all sections of the country."

Thus Dan Rather seemed to be overly diffident a few moments later when he said, "The Jimmy Carter forces have to be hearing faintly the first whispers of the ax."

In some respects it was the night of the two gippers: Ronald Reagan, ushering in his own new era, and the incomparable Walter Cronkite, ushering himself out for what had been announced as his last fling at reporting presidential returns. Although NBC News may have been first to hand the country over to Reagan, it wouldn't seem quite official until Cronkite confirmed the results himself.

With Rather, his successor, Cronkite seemed a trifle testy. After Cronkite reported that Carter learned Monday night he couldn't win, Rather came on with some detail on that story. When he finished, Cronkite asked him, "What time was that?" Rather, looking flustered, said "Uh, last night." Cronkite replied, "Same report then, huh?" and moved on brusquely to other matters.

But to reporters like Bill Plante, Cronkite would make supportive remarks, like "Carry on." He was the grand old coach urging his team to one last victory and casting a disgruntled glance over his shoulder at his own replacement. Maybe this was more dramatic than the decline and fall of Jimmy Carter.

NBC News, for all its computer wizardry, seemed hampered on the air by the limited participation of veteran David Brinkley, recovering from a gall bladder operation. ABC News had the best display of information on the screen, but all three networks were dazzling in their rapid display of data -- not only vote totals, but quick fixes on why people voted the way they did, how inflation figured in their decisions, which candidates they distrusted the least, and so on.

Among the livelier performers was ABC's Koppel. When Mary Louise Foust lost the Kentucky Senate race early in the evening to Wendell Ford, Koppel said that Foust had vowed she was only going to spend $100 on her campaign. "It looks as though she might have spent 95 too many," he added.