Washington woke to shattered glass and wailing sirens. German shepherds prowled the back rooms of empty buildings, sniffing for bombs; riflemen crouched on roofs, watching for assassins. The sounds of rush hour competed with the low rumble of motorcycle escorts and the sputtering whine of helicopters overhead. The city that sleeps through August was jarrd yesterday into fall and the realities of an international capital.

Police cars plunged through traffic-clogged streets in downtown Washington, roof lights flickering. Behind them, sleek black Cadillacs whisked ambassadors and dictators past the citizens, who had come to shout at them, to a Kennedy Center luncheon and the historic treaty-signing ceremony that climaxed the day.

It was suddenly a city with the world in its streets. Two midnight explosions had trumpeted someone's fury - anti-Castro Cubans claimed respobsibility - and the raging continued into the next night: Dominicans outside the White House demanding human rights, Chilean supporters in Lafayette Park denouncing ruler Augusto Pincohet: American conservatives opposing the Panama Canal treaty on Capitol Hill. Police in reinforced numbers danced through a manic ballet of traffic direction and crowd control, and Washington kept on moving.

Something has happened here, something sometimes frightening and at the best of times, exhilarating. The internal turmoil of other nations has begun to be vented in Washington.

"Cubans?" a police officer shrugged, gazing at the blown-out debris outside 16th and L Streets NW yesterday afternoon. "When you're in the melting pot of the world like this, it could be anything."

So it could. In the last few years a chilling array of international passions have been played out here, inspired by religious fervor by personal passion, by frenzied nationalism and sometimes by all three.

A bomb blows up the car carrying Orlando Letelier, former ambassador to Chile and fervent critic of the current Chilean junta: a year later, the murder is still being probed here, with Cuban exiles and Chilean officials the suspects, Hanafi Muslim Abdul Hamaas Khalis, driven by vengeant grief and religious passion, presides over the capture and seige of three buildings full of Jews, visiting foreign students and other innocent victims until Egyptian, Iranian and Pakistani ambassadors use poetry and the deep mystery of the Koran to urge their release.

The French embassy has been bombed. The Yugolsav embassy has bombed. The Russian embassy has been bombed. Newspaper stories reveal how the secret service agencies of the world now prowl Washington, seeking dissident countrymen: SAVAK from Iran; DINA from Chile; KCIA from Korea.

The city's streets, parks and churches reverberate season after season with the voices of Iranian students protesting policies of the shah, Eastern Europeans protesting the domination of the Soviet Union. Taiwanese protesting U.S. recognition of mainland China, Ethiopians protesting a coup across the ocean in their native land.

Arab students fill the Arab Information Center on Connecticut Avenue in 1976, protesting the Syrian invasion of Lebanon - "They're expressing their views," an official tells the papers. Baptists burn a flag in front of the Soviet Embassy, demanding the release of a Baptist family in Riga, Latvia. Thousands of Ukrainians gather at the Washington Monument and parade to the statue of an honored Ukrainian poet: nearby, Indians for Democracy hand out leaflets marking the first anniversary of India's state of emergency.

And two Bulgarians spend a week of America's Bicentennial year standing in front of the U.S. State Department, in the airless summer heat, saying their daughters cannot get out of Bulgaria.

"It becomes apparent that we're not only a national capitol," D.C. Police Sgt. Dave Shannon reflected yesterday after another year of international protest and intrique here. "We're a world capitol."

The D.C. Police have a bomb squad now - four men and four German shepherd dogs who can sniff out explosives. Before 1970 it was just two men who spirited the bombs away and hoped they would not explode. Then concerned about domestic violence, they expanded, and began learning more about terrorism.

Now there is a new focus to all that study. The U.S. Park Police have contingency plans to combat international terrorism at the national memorials here. "It's a reality now," Shannon said. "It can happen here."

Still, there was a good-natured resilience to it all yesterday. A bomb threat cleared out 1629 I Street NW in midafternoon. "I'm not kidding," the young female caller reportedly said.

On the sidewalk outside a woman tugged at a police officer's sleeve. "If this bomb isn't going off until 4 and it's 3:09 now," she demanded, "why can't I run up and get my pocketbook and go home?"

In front of the White House, an elderly woman wearing a magenta head scarf pushed her shopping cart up close to listen to Dominican protester's rapid tirade in Spanish. The woman nodded, and then leaned forward, imparting a secret. "You won't get any help from him," she said, grazing toward the White House with distaste. "He held the campaign when the country was under martial law, which made it totally illegal."

She nodded, evidently satisfied with her assessment, and went away, waving grandly toward the Dominicans and the President and everybody else in the world. "Communists!" she cried.