"Just reading the Equal Rights Amendment, it's amazing to me that anyone could oppose it," said Sen. John Glenn (D-Ohio) last night, looking out at a crowd that had doubtless read it many times. "It's so simple and straightforward and so right and so just."

Glenn, whose own political aspirations will depend on more than just the reading of the Equal Rights Amendment, was among a half dozen members of the Senate and House putting into words what the National Organization of Women was celebrating: the reintroduction of the ERA in Congress.

"We feel strongly that the reintroduction is a considerable tribute to the impact women had in the 1982 elections," said newly elected NOW President Judy Goldsmith. "When a message came through clearly that women intend to be centrally and fully involved in the political process, that message was heard and responded to by a very enthusiastic reintroduction of ERA in Congress."

The House reintroduced the ERA as its first order of business Jan. 3, calling it House Resolution 1, with 210 cosponsors. That number has since grown to 232. The Senate introduced it Jan. 25, with 54 cosponsors, now 56. The amendment needs 290 votes to pass in the House, and 67 votes in the Senate.

"Until women have the same rights as men on this great green earth," said Goldsmith, quoting Susan B. Anthony to nearly 200 NOW supporters at a reception at the Foundry in Georgetown, "there will never be another season of silence."

"Don't be scared off by my conservative friends in the Senate," said Sen. Joseph Biden (D-Del.). "I think some of them will see God before the next election. She will send them a message."

Some members of Congress got the message in the last election.

Rep. Peter H. Kostmayer (D-Pa.), defeated for reelection in 1980 by 3,000 votes, was reelected last November.

"Largely due to NOW," said Kostmayer, to applause. "When you win a close election like that, every bit makes a great deal of difference."

Rep. James R. Olin (D-Va.) was next. "Thanks to NOW," he said, "I was able to become the first Democrat in my district to be elected (to Congress) in 30 years."

Said Rep. Bruce A. Morrison (D-Conn.): "The reason I'm here in Washington has a lot to do with the National Organization of Women and the kind of support it gave me in my campaign. We built a grassroots coalition that made the difference."

"This is a movement gathering momentum," said Rep. Douglas Walgren (D-Pa.). "There is no way it is going to be denied."

NOW's outgoing president Eleanor Smeal didn't even try to disguise how sweet it was to hear such testimony, particularly after the failure of the ERA to win approval by last year's June 30 deadline.

"It's so good seeing some of the Congress people we helped elect. NOW won sixty percent of our races," said Smeal. "We were a political force out in the grass roots."

The 163rd anniversary of Susan B. Anthony's brith had been one reason for last night's celebration, but as occasions go, by itself it wasn't exactly the kind of thing that would bring senators and congressmen rushing down from Capitol Hill.

And striking a note Democrats are likely to make much of in the campaign months ahead, Glenn said, "A line I can tell you always gets a response from an audience is to say, 'Making one woman a justice does not bring justice to American women.'"