When Mark Twain, the master of barbed wit, talks about the curious human race, audiences snap to attention. But when an unknown theology student pontificates on war, peace or the SALT treaty, he's more likely to be greeted with polite interest or embrassing snores.

Bill McLinn's no fool. Wanting an eager auidence and the chance to influence the public on important social issues, he had but one choice.

He became Mark Twain.

"Ladies and gentlemen, he is a gentleman whose great learning and veneration and love for truth are in perfect harmony with, yet only exceeded by his high moral character and majestic, imposing presence. I refer -- ah -- in these -- ah -- vague, general terms -- ah -- to myself," said McLinn's Twain, introducing himself recently to a group of 150 State Department officials.

"It is wonderful to observe the calm confidence of a Christian -- with four aces!" said the bushy-haired gentleman.

Only a few minutes into his presentation, McLinn had the lunchtime crowd in his hands. For the next hour, the stately Twain spewed biting attacks on humanity.

"I could state at this moment there are two men who are most remarkable. Hodding Carter [the State Department's top spokesman] is one and I am the other one. Between us, we cover all knowledge. Mr. Carter knows all that can be known and I know the rest," McLinn said behind a walrus mustache.

Using only Twain's words, he talked of his days as a news correspondent covering the "inmates" at Congress, "a body of men with tongues so handy and information so uncertain . . . [who] could talk for a week with out every getting rid of an idea."

After writing off power struggles and war as absurd, Twain reached up and removed his caterpillar eyebrows.

Then off comes the mustache, the wig, the coat and tie, the baggy pants.

And underneath -- is McLinn, a 35-year-old theology graduate, lobbyist, former Capitol Hill employe -- dressed in a suit and tie.

"This is when I usually talk about SALT," he said, wiping away the last bits of glue and makeup.

But he changed his script for the knowledgeable State Department crowd. He usually spends an hour explaining the SALT treaties in layman's terms or, when called upon, debates the treaties.

Now, after six months and 80 performances across the country, McLinn says he has gotten favorable newspaper reviews, while persuading many listeners to support the SALT II treaty.

And, he's broke.

Charging only minimal speaking fees at colleges, and accepting whatever donations churches offered, McLinn earned $3,000 on his recent tour. But he said his traveling expenses, costume and wig cost just about that much.

If he's unable to set himself up in business as a lobbyist or find a sponsor, McLinn said he'll borrow more money to continue performing with a new show, Mark Twain on issues of the '80s.

McLinn said his material is different from the show that actor Hal Holbrook has played on Broadway and has copyrighted his show -- and contends that it is more accurate than Holbrook's.

McLinn, whose father was a Christian Scientist reader and whose mother is a Presbyterian minister, belongs to First Congregational United Church of Christ here, where Twain spoke 80 years ago.

With a bachelor's degree in government, and separate master's degrees in theology and ethics and international relations and law, McLinn has held a number of jobs; a staff assistant for the Department of Justice, a lobbyist for the United Presbyterian Church in the U.S.A., a legislative aide for Rep. Andrew Maguire (D-N.J.), and a faculty lecturer and adviser in the political science department at the University of San Diego.

Although his savings are nearly depleted and he's eating with the help of food stamps, McLinn said he'll pursue his Twain routine -- and hopefully develop it into a career.

McLinn has worked on the presentation for five years with the help of two professional theater directors, who gave him advice on staging and dialogue. He also spent months researching details of Twain's personality and gathering, compiling and editing Twain's writings.

His next local performance will be at 7 p.m. Arpil 20 at First Congregational Church at 10th and G streets NW.