They stook in quiet vigil under a canopy of multicolored umbrellas, hundreds of reporters and television crews and passerbys, waiting outside George Washington University Hospital's emergency room in a pelting rain. Ronald Reagan had been shot, the president of the nation was undergoing surgery, and politics were momentarily forgotten.

"When happened? How is he? Will he live?" came Viola Lawson's questions in rapid fire. A District of Columbia employe on her day off, she had heard the news of the assassination attempt and come right to the hospital.

"I mean," she said, "I didn't vote for the man, don't even like him, but hell, you have to feel like somebody hit you in the stomach."

Traffic on Washington Circle, where the entrance to the emergency room is located, came to a virtual standstill as people stood everywhere, lining the rain-swept streets and waiting for some news, surprised and aghast.

At about 3:30 p.m. White House spokesman Lyn Nofziger appeared, his hair drenched and beard tousled.

"I can confirm the president has been shot," he said. A spontaneous collective sigh rose from the crowd.

Reporters scattered across Washington Circle to find telephones to report his words. At the One Washington Circle Hotel, employes were glued to a television set. One staffer recalled another attempt on a president's life.

"I remeber being on the front step at home when my mother came out and told me that President Kennedy had been shot. I remember that she was crying and I started to cry and it seemed like the whole street was pouring out of their houses and crying too.

"But with this, I don't know. Everybody doesn't love Reagan the way they loved Kennedy, but after all, he's the president. I can't believe this has happened."

Back outside, the downpour came faster and Tim Kraft, a construction worker, his blond hair stringy and wet, stood on the grass and gaped at the scene before him. "That guy, whoever he was, had to be crazy to shoot the president. No matter how bad things are that can only make them worse."

From across Washington Circle, the wail of a siren pierced the gray day and a District police squad car, red lights flashing, roared into the driveway of the hospital emergency room. Police and Secret Service men, guarding the entrance, scattered and two officers jumped out and gathered from the backseat two boxes of O-negative blood for use in President Reagan's operation.

Nearby Ross Hall was transformed to a temporary press room. The university's medical students, who had come in droves with books in hand, were asked to leave. "This is our school," complained one, as he was ushered out by a burley campus security guard.

As news reporters milled around, a reporter for the Mutual Broadcasting System began telling three colleagues that he had surreptitiously entered the hospital behind Mrs. James Brady, the wife of Reagan's wounded press secretary. The reporter gave secondhand accounts of Reagan's and Brady's conditions, explaining how he had see Brady lying on a table in a room he called the head scan room. Suddenly, he was besieged with questions from more than 100 reporters who had gathered around him.

With more and more reporters trying to elbow their way into earshot, the reporter stopped his commentary and was escorted to the front of the room where he held a press conference on his own. At about 5 o'clock, the reporter was interrupted by another appearance by a haggard-looking Nofziger. He could offer few details but did recall, almost incidentally, a remark made by the president on his way to surgery.

As he was going down the hall on the stretcher, Nofziger said, he looked up at Mrs. Reagan and said, "Honey, I forgot to duck."

Said one reporter, "It's lucky we have a cowboy for a president."