The careful courtesy that sometimes leads observers to confuse the Senate with an Old Pals Club took it on the chin yesterday in an unusual exchange between two senators on national television.

The verbal fisticuffs on NBC News' "Meet the Press" involved Sen. Daniel Patrick Moynihan (D-N.Y.), who was elected 10 years ago, and Sen. Phil Gramm (R-Tex.), a freshman and coauthor of the Gramm-Rudman-Hollings budget-balancing law.

Gramm, defending the budget law, called himself "one of the strongest supporters of national defense" and termed Moynihan "one of the weakest." Moderator Marvin Kalb attempted to steer the discussion in another direction, but an indignant Moynihan erupted in defense of himself and with a lecture for Gramm.

The exchange went this way:

Gramm: "To show you what miracles there are in Gramm-Rudman . . . we have on one side here one of the strongest supporters of national defense in the country, and one of the weakest. And yet. . . . "

Moynihan [chortling]: "Oh, wait. Wait. Wait. Come on, friend. Name a bill, name a bill."

Gramm: "And yet now, suddenly, we're having all the Democrats who have not supported the president on defense, who are saying, 'My God, Gramm-Rudman's going to decimate defense.' Well, it's not going to decimate defense. We're not going to have the across-the-board cuts. We're going to make hard choices because we're not going to have any alternative."

Kalb: "But senator, are you going to allow, are you going to allow the president to have a 3 percent increase?"

Moynihan: "Marvin -- Marvin, I'm not going to allow my voting record to be misrepresented. [To Gramm] You're one year in the Senate, fella. You don't do that to another senator. I have voted with one exception for every defense appropriation bill since I've come to the Senate. And this year, under Gramm-Rudman, for the first time in 15 years, the dollar amount for defense spending is going down. First time in 15 years under your bill. I would not misrepresent you; don't misrepresent me."

Gramm did not apologize, but he extended and revised his remark to accuse "the national Democratic Party" generally of not supporting the president.

Gramm, elected to the House in 1978 as a Democrat, quit the party in 1983 after House Democrats accused him of disloyalty to the party, and ousted him from the House Budget Committee. Gramm resigned from the House, then was reelected from the same district as a Republican. He was elected to the Senate in 1984.