Sen. Charles Percy (R-Ill.) referred specifically to B'nai B'rith and the American Israel Public Affairs Committee when he said that the American Jewish community was not supporting Israel's rejection of President Reagan's peace plan. He meant that only some of the leaders of the community have broken ranks with Israel on this issue.

White marble, shimmering silk and enough pomp and royalty to start a new kingdom launched Washington's tuxedo season at the Corcoran Gallery last night.

"We've had kings and queens here before, but never such a bevy of royal highnesses," said Corcoran president David Lloyd Kreeger, shuffling from Scandinavian prince to princess, six of whom were on hand for the opening of "Northern Light: Realism and Symbolism in Scandinavian Painting, 1880-1910."

And while 500 of Washington's glamor class gossiped and nibbled delicately on reindeer, as usual the political business of the day cropped up somewhere between the bar and the buffet.

"I had the speaker of the Israeli Knesset in my office for coffee today and I told him that the American Jewish community was obviously not with Israel," Sen. Charles Percy (R-Ill.) said to Swedish Ambassador Wilhelm Wachtmeister. "I said I really think Israel has lost its senses opposing the Reagan plan like this."

"How did he explain himself?" asked Wachtmeister.

"He really couldn't," said Percy, chairman of the Senate Foreign Relations Committee. "I told him that now it seemed that [Israeli Prime Minister Menachem] Begin and [Libyan ruler Muammar] Qaddafi were in agreement [by opposing the plan]. Really, what makes Begin any different from Qaddafi now?"

"Is he a Begin man?" inquired Wachtmeister about the Knesset speaker.

"Much more liberal," replied Percy.

Later, Percy told a reporter that he had admonished the speaker of the Knesset, Menachem Savidor, for Israel having taken a position where Begin, Qaddafi and Rifaat Assad, brother of the Syrian president, were all condemning the plan. "Now what could they all possibly have in common?" asked Percy.

Across the room, Senate Majority Whip Ted Stevens (R-Alaska), was more concerned with domestic business. "The Senate will probably override the veto too," he said of the $14.1 billion supplemental appropriations legislation whose veto by Reagan was overridden by the House yesterday. "I predicted it would be overridden. But I'm sad to see it come true."

Last night a smattering of the diplomatic community, Congress and the Reagan administration dined on three kinds of salmon -- 130 pounds of smoked and marinated -- and rubbed elbows with the royalty, most of whom kept disappearing into the VIP rooms. The opening exhibition was part of "Scandinavia Today," the 15-month celebration of Nordic culture.

Moving the royal Scandinavians through the exhibit was a story in itself. Flashes exploded unsympathetically from every corner of the gallery for the perfunctory photo opportunities.

Prince Henrik of Denmark, here representing his wife, Queen Margrethe II, who at the last minute had to remain in Denmark for the restructuring of the government, obliged the army of photographers readily by removing his wire-rimmed glasses for the pictures.

"I guess I can put them on now," he said as the last flash and click came from the crowd. "They seem to be finished."

They were, and for the most part so were the royals. They stayed only for a little while longer and by 9 o'clock were saying an emotional good-bye to each other in a private room. Some will be going on and others will be heading to Minneapolis for another celebration.

The party went on. And on. Former treasury secretary G. William Miller tried mustard on his salmon. FBI Director William Webster tried to rearrange the tennis game he missed yesterday. One woman fainted from the heat. Another kicked someone who stood between her and a senator she hoped to talk to. Loraine Percy said she thought David Lloyd Kreeger was as cute and comforting "as an old shoe."

And Ulla Wachtmeister, the Swedish ambassador's wife, stood close by her brand-new cook, 24-year-old Peter Svensson, who recently came to this country from Sweden. She had lent him to the event. As he sliced, she monitored. "I'm here for moral support," she said. "You know, he's so new. Isn't he sweet? I want to make sure everything goes right."

After the royalty, the food was the main attraction.

"Art openings are never to see art," said one member of the Corcoran's board. "I just came here to socialize. I'll come back for the art tomorrow."