Sen. Howard Baker, who's aiming for the presidency in '88, got some unsolicited job counseling last night.

Said President Reagan: "Here is a man with a distinguished career in the Senate, he's a lawyer of distinction, he's returning to Tennessee and the thought has occurred to me -- the United States Supreme Court. We could use a little justice."

Reagan may have been dangling a carrot or launching a trial balloon, or just kidding the Senate majority leader about his height. Baker's 950 friends just laughed it off at a $1,000-a-plate roast for him at the Washington Hilton. Even when Baker isn't being roasted to fatten up his Republican Majority Fund, he stands 5-foot-7.

Roaster Lamar Alexander, the Tennessee governor, said, "I don't know what Howard will do in the next four years, but he better do it quick. He was in Wartburg, Tenn., the other day when a woman looked him over and said, 'Didn't you use to be Howard Baker?' "

U.N. Ambassador Jeane Kirkpatrick, who confessed that she really didn't know him -- only his work on the Senate Foreign Relations Committee -- noted shutterbug Baker's Potomac qualifications: "He may be the next secretary of state -- or he may be the next White House photographer."

Sen. Alan Simpson (R-Wyo.) counseled Baker to at least "look like" he was having a high old time: "Those who travel the high road of humility in this town are not really troubled by heavy traffic."

Baker, who called the $1.1 million raised for his PAC "just barely worth it," remembered another time his ego had been bruised. That occurred shortly after he and the former Joy Dirksen were engaged and went to Illinois to meet her relatives. Among them was Sen. Everett Dirksen's twin brother. As Baker, feigning pain, told it, " 'Ev,' he said, 'he's not very big is he?' And Senator Dirksen said, 'No, but he's loud.' "

Baker was a man of sufficient stature, nonetheless, to warrant the presence of columnist William F. Buckley Jr. on the dais. As the evening's emcee, he was responsible for introducing the roasters and the roastee. The introductions were characteristically Buckleyesque.

"That's the damnedest introduction I ever had," said Simpson. "I'm not sure I know what it means," said Baker of his.

Nobody had any doubts, however, about the meaning of another introduction. "My old friend, the president of the United States," said Buckley.

Reagan wasted no time in turning the spit.

"This occasion is billed as a roast. But to the uninitiated, that has nothing to do with the entree . . . I must confess I'm not much of a roaster," said Reagan. "I believe that if you can't say anything nice about a person you shouldn't say anything at all. So in conclusion . . ."

The crowd broke into applause.

Of Baker's leadership qualities, Reagan said he had long admired his "cool, calm, collected" way of doing things.

"Just Monday we had a leadership meeting there in the Cabinet Room, and Howard took over almost immediately. He said, 'Here it is Monday and tomorrow is Tuesday and the day after that is Wednesday and half the week's gone and we haven't done a damn thing,' " said Reagan.

But the president said he was grateful for all Baker has done to help him. "I asked for a 30 percent tax cut, and he gave me 25 percent," Reagan said, and then added another needle about Baker's height. "Some people might think you came up a little short, Howard."

The president recalled his inauguration on the steps of the Capitol and how Baker told him he would be with him "through thick." "I said, 'What about thin?' and he said, 'Welcome to Washington,' " said Reagan.

Looking around the crowd that included high-powered Washington officialdom from Capitol Hill and the Cabinet, Reagan kidded that it was an impressive assemblage. "I see that virtually the entire Cabinet is here, which explains why deputy chief of staff Mike Deaver has gone to sleep already."

Reagan told Baker that he had won a place in history. "He made the world safe for snail darters," joked the president, referring to the Clinch River reactor project in Baker's home state.

But Reagan also had his serious moment in talking about Baker, who is retiring after 18 years in the Senate and will keep his Washington residence in addition to the family place in Tennessee.

"Howard Baker has been a true friend. He's been a lion in support of the cause which unites us. And you will be missed more than you know. I'm not going to let myself think about it," said the president, "because it hurts too much."