Jeane Kirkpatrick's first speech to a grass-roots Republican gathering since she formally became one herself was interrupted not once by either applause or laughter. That suggests forecasts of instant elevation to her new party's national ticket may be premature.

She did exhibit political star quality in attracting more than 900 paying guests to a Monday night dinner and keeping their hushed attention while pitching President Reagan's Central American policy. But a plea for help for Nicaraguan freedom fighters, delivered in professorial lecture style, was not the message they came to hear.

While savvy Republican insiders believe Kirkpatrick when she unequivocally denies any intent to run for office, they value her as necessary new blood who might end up as vice presidential nominee in 1988. But her Wilkes-Barre debut suggests this former backstage Democratic activist will experience adjustment problems as an out-front political performer and -- less obviously but more importantly -- as a member of a party whose spiritual concern is the budgetary bottom line.

Kirkpatrick was here, two weeks after leaving the United Nations, at the behest of one of the Republican Party's remarkable young figures. Marc Holtzman has been engaged in big-time Republican politics since his late teens and now, at 25, is running for Congress. With tickets priced up to $1,000 (for attending a pre-dinner reception and being photographed with Jeane and Marc), the tyro candidate netted over $100,000.

Kirkpatrick made it happen. Harry Lee, who runs a resort conglomerate in the nearby Poconos, brought six friends and business associates 60 miles from Stroudsburg to Wilkes-Barre to see the forer ambassador, whom they consider the rising new Republican star.

Before she spoke, Lee expressed hope that her speech would propose a significant new approach toward arms control or perhaps federal deficit reduction. What if, we asked, she talked about Nicaragua? That, Lee replied, would be "a little provincial."

After Kirkpatrick delivered a closely reasoned argument why Marxist Nicaragua poses a threat to U.S. security, Lee confessed that "in a sense" he was disappointed, but said he and his associates were impressed by her personality. One of his business partners, Harry Ahnert, called her speech "excellent, but not rousing."

Indeed, one political pro in the audience confided that she could again use the help of sometime Reagan speech coach Miles Martell, who shaped Kirkpatrick's prose and delivery for her Republican National Convention triumph last summer that made her an overnight political sensation. Without him, she has reverted to the university lecturer's convoluted sentence structure and finds herself facing rapt but not demonstrative listeners.

However, her problem on the Republican stump goes beyond style to substance. She is a heroine of the conservative movement but not one of its foot soldiers fully embracing its agenda. Bona-fide intellectual Kirkpatrick is not ready to swallow whole Reaganite positions on issues she has not yet thoroughly studied -- including tax reform and abortion.

Moreover, while she could no longer remain even nominally associated with a Democratic Party whose leaders cannot survive if they oppose communist expansionism in Central America, she will have trouble fully relating to a Republican Party with the soul of a bookkeeper.

While Kirkpatrick in Wilkes-Barre did not deliver the deficit-reduction pitch many in the audience wanted, Republican congressional leaders in Washington were pressing President Reagan to give the budget priority over Nicaragua. She cannot bring herself to believe that dismantling Amtrak is more important than saving the contras.