Then there is the matter of pork. Rare is the politician, of whatever party, who does not welcome costly new Federal projects in his state or district, especially in an election year. Kasich is that rarity, which has landed him in a row with another House pooh-bah, Representative Bud Shuster of Pennsylvania, the chairman of the Transportation Committee. Shuster wants to spend a fifth of the projected budget surplus over the next five years, roughly $27 billion, on roads, bridges and the like; Kasich marched into a meeting of the National Governors' Association and told the startled members that the states should be able to ''raise and spend their own gas taxes as they see fit,'' rather than depend on Washington. He wants to spend half the surplus on tax cuts and half on debt reduction. The highway lobby is so riled by Kasich's stand that it recently ran a series of radio spots against him on stations in Columbus.

Which fazes Kasich not in the slightest. Not much does.

He hammers tirelessly at his message -- shrink the Federal Government, send tax dollars back to the states and cities, push decisions down the chain, emphasize individual responsibility for education and health care. In a recent speech, he said, ''The great issue of the future is whether we take our power back or let powerful institutions in Washington continue to frustrate our will.'' The echo of Ronald Reagan is plain (and, I suspect, intentional).

An impish, round-faced man of 45, whose eyes almost close and whose pebbly cheeks crinkle when he smiles, Kasich is earnest, aggressive, often abrasive, yet somehow charming. He wears his ambition on his sleeve, but he gets away with it. If he raises enough money and decides to press on with a Presidential bid, he told Cokie Roberts jauntily on ABC News's Sunday morning show, ''I'm going to need you and Sam to go out and put up yard signs, and maybe George can drive the truck.''

''There's a certain roughness about him,'' says Ed Goeas, who is expected to do Kasich's polling.

In his 15 years in Washington, Kasich has mastered not only the arcana of the budget but also the complexities of military affairs (serving on the National Security Committee). A speechmaker since 14, when as a Catholic altar boy he occasionally took to the pulpit, he is fluent on his feet. But his gestures too often make him look like a runaway windmill and his metaphors sometimes run off the track (''a burning coal deep inside your souls'').

Like President Reagan, he has the gift of instant credibility. People who hear him believe him. After a forum at the University of New Hampshire on one of Kasich's first forays into that crucial, first-in-the-nation primary state, I overheard a group of students, standing in a wintry rain, exchanging impressions. One said, ''You know he believes what he's saying, whether you agree with him or not.'' Another added: ''There's no Washington in him at all. He's not cynical.''

No one doubts Kasich's passion or his formidable energy. But he has yet to persuade many of the party's leading lights that he has the maturity that the Presidency demands. Senator John McCain of Arizona, a potential rival for the Presidential nomination, describes him as ''a fine, fine young man, one of the best we have,'' but adds, ''he has a hair-trigger temper.'' Richard V. Allen, one of Ronald Reagan's national security advisers, has counseled Kasich on foreign policy questions and fondly refers to him as ''my young revolutionary.'' Kasich's Budget Committee buddy, Representative David L. Hobson, 61, says, ''He's kind of my ward.''

Kasich has fought for most of his political life against this notion that he is too young, glib, immature and impetuous. One of his mentors, John O. Marsh Jr., a former House member from Virginia who served as Secretary of the Army in the Reagan Administration, remembers telling Kasich when he was elected chairman of the Budget Committee, vaulting over a much senior colleague: ''You've got a lot of responsibility now. Don't do anything stupid.'' In those days, some members called him ''the unguided missile.''