ANNAPOLIS -- A joke circulating among legislators here has Saddam Hussein asking a mirror, "Who's the craziest ruler of all?" Puzzled at the answer, he wonders: Who is this William Donald Schaefer?

Never a wallflower with his emotions, the Maryland governor in recent weeks has insulted the state's Eastern Shore by calling it an outhouse, tracked down a motorist to upbraid her for gesturing at him, and dashed off sharply worded responses to private citizens who had written him critical letters.

"Dear David Nottingbrain!" the governor wrote to G. David Nottingham, of Carroll County, author of a satirical attack on state spending in a local newspaper. "Your letter sounds like a frustrated little boy . . . . I pay taxes on real estate, federal and state!! Most likely more than you!!"

"He told me, 'Your letter pukes with sarcasm,' " said Charles R. Jones, referring to a handwritten reply he received from Schaefer.

A sharp tongue and thin skin have been part of Schaefer's governing style for years, and many officials and members of his staff have felt the sting. Defenders say this leadership by intimidation gets results within the bureaucracy, but the governor's approach may not be as well received by the public.

A recent Mason-Dixon poll indicated Schaefer's job performance rating has dropped significantly in the last year, with 50 percent rating him good or excellent, compared with 68 percent in January 1990. And while deciphering his mood swings has become something of a cottage industry in Annapolis -- his meetings with legislators are considered a success if a full-scale explosion is avoided -- his reference to the Eastern Shore earlier this month as a "{expletive}-house" stoked open debate about whether the former mayor of Baltimore had gone off the deep end.

When Schaefer's mental health became a topic on one of the radio talk shows he chronically monitors, the governor felt compelled to call in with the message: I am not a kook.

"I am not going to stand this," Schaefer told listeners to WBAL's Ron Smith show. "I'm fine; never felt better."

Two days later, appearing before the State House press corps with an "accentuate the positive" button pinned to his lapel, he assured reporters, "My mind is as clear as it has ever been."

Some are not so sure.

"I'd like to get a punch in at him," said Charles Bassford, of Caroline County, whose wife wrote to Schaefer and received a reply calling Eastern Shore residents "narrow-minded, cynical, clannish, unworldly, afraid of change, and unsure of themselves."

Bassford said it was inappropriate for someone in Schaefer's position to insult a private citizen because "he's a governor. It packs more of a punch when he says something."

"The whole thing is hilarious," said Nottingham, a part-time teacher. "I have no bones with the man as a person . . . . I just have the feeling that there is a case of paranoia here."

Indeed, Schaefer, in a talk show call this week, informed one persistent but anonymous critic that he has identified his voice as that of a former Baltimore employee.

"I suggest he give me a call . . . . I bet he never will. He likes to hide," Schaefer said.

In another instance, after a motorist flashed what the governor insists was an obscene gesture at him, Schaefer traced her address through the Department of Motor Vehicles -- as any individual could have done -- and wrote to the driver, "Your action only exceeds the ugliness of your face."

"She did not give me a thumbs down, she gave me a finger up . . . . And I am supposed to take it?" asked Schaefer, who contends his eye-for-an-eye approach is the only way to deal with his harshest critics.

Legislators say it is unclear whether Schaefer's caustic style will ever cost him support in the General Assembly, where lawmakers such as House Speaker R. Clayton Mitchell Jr. (D-Kent), an Eastern Shore native who was angry with Schaefer's remark about that area, control the fate of the governor's legislative initiatives.

It certainly cost him during the recent campaign: Schaefer still frets over the fact that he won less than 60 percent of the November vote, and in the days after the election he had tacked behind his office desk a map with the counties he lost shaded in pink. Since then, he and his media staff have worked to restore the "regular guy" image Schaefer felt was tarnished by Republican allegations that he is overbearing, mean-spirited and a spendthrift.

"They made me sound like Donald Trump, not Don Schaefer," he said during his inaugural address.

The recent outbursts haven't helped. "It really is refreshing in some way that there is a politician who is not plain vanilla, but it does not help him build consensus," said Del. Brian E. Frosh (D-Montgomery).

House Appropriations Committee Chairman Charles J. Ryan (D-Prince George's) noted that Schaefer once donned a metal helmet to declare war on a Senate committee and put on a pair of prank eyeglasses at his State of the State address.

None of that hurt the governor because "it seems to be an episodic kind of thing," Ryan said. If the "episodes" become more frequent and severe, it could damage his credibility, Ryan said.

The governor dismissed controversy over the Eastern Shore comment, saying the remark was "silly" and "off-the-cuff." But it was not the first time he displayed contempt for jurisdictions that vote against him.

After the 1986 election, Frosh recalled, Schaefer said Montgomery County was populated with "flakes."

Schaefer and his aides say that those who get upset by the governor's commentary miss the point. His responses are always tailored to match the criticism, they contend.

The uninformed or crude get as much in return, said Schaefer aide Daryl C. Plevy, but the well-intentioned, even if critical, get more personal attention than is usual for a governor. Schaefer reviews many of the more than 200 letters he gets daily from the general public and responds when he can in writing, sometimes to as many as 30 a day, Plevy said.

Most, Plevy said, are sincere letters that get sincere replies. Only a few are of the "Nottingbrain" ilk.

"I wear my feelings on the sleeve. And the day I don't, I resign," Schaefer said last week.

Plevy said Schaefer's remarks reflect not so much antagonism toward critics as his own insecurity.

"Although the perception is he's blaming them, he's really blaming himself," Plevy said. "He reacts directly and personally . . . . I've sat in his office tons of times when he called people who wrote nasty letters . . . . He's having a dialogue with them. He becomes pen pals with a lot of them."