Loner Gary Hart works hard to chart an independent course

Early this year, well before he turned conventional wisdom into foolishness by winning in New Hampshire, Gary Hart sat in the chamber of the US Senate. On this rare visit to the Capitol between campaign stops, he turned to a colleague.

''I'm going to be there,'' said the Coloradan to a nonplused Sen. Alan K. Simpson (R) of Wyoming. And then he proceeded to forecast the early rounds of the presidential race. He'd start out behind, he told Senator Simpson, but first Sen. John Glenn (D) of Ohio would fall back. ''And then it'll be a two-way race, and then I'll be there,'' concluded Senator Hart.

The once skeptical Simpson, recalling the words, has just fired off a ''you told me so'' telegram to the candidate.

If Gary Hart has been unsurprised by his victories in the race for the Democratic presidential nomination, he may be the only one. Most of the country has been left with mouths agape, wondering who this thick-maned and ruggedly handsome man suddenly closing in on the presidency might be.

Even his own colleagues are amazed.

During his nearly one decade in the US Senate, Hart has hardly made an big splash. Holding no leadership position, he has gained a reputation as a hard worker, inveterate reader, and a thinker. It is almost a cliche to call him a loner in the generally clubby Senate, but almost everyone describes him that way.

In the country at large, no single bill or issue has made his a household name.

During his first term, Hart was offered an opportunity to grab headlines as chairman of the Senate panel investigating the nuclear accident at Three Mile Island in Pennsylvania. He said no thanks and ran the proceedings with an even hand.

''He handled it quite responsibly,'' says Senator Simpson, who was the highest-ranking Republican on the investigating committee and who had feared harangues against nuclear power.

In Congress few saw glimpses of great oratory from Hart, whose speeches have been characterized as dull and overburdened with detail. ''Hart has spent too much time among the analysts and experts, and too little time trying to boil down his thoughts into pithy phrases the voters will understand and remember,'' huffed a 1981 profile in the Washington Monthly.

In fact, the Colorado senator had focused on things other than oratory. Since arriving in Washington in 1975, the Denver lawyer, who once directed the failed presidential campaign of George McGovern, has concentrated on issues. Methodically he has been reading, meeting with experts, and carving out positions in areas ranging from defense to the economy. That process has generated the ''new ideas'' that he is touting on the campaign trail and which he outlines in his book, ''A New Democracy.''

While few of the ideas are exactly new, they represent an effort to form cohesive policies that do not fit neatly under the liberal or conservative label. And while Hart is not the sole owner of the ideas, he has been in the forefront pursuing them.

His chief accomplishments, by all accounts, are in the area of military reform. Although he ran the 1972 McGovern campaign on a tide of youth and anti-Vietnam war sentiment, Hart as a senator wasted no time dispelling an antimilitary image. He plunged into a thorough study of the military, picked a talented team of reform-minded staff members, and began designing an armed forces overhaul. He even joined the naval reserve at age 44.

''I do think he can legitimately claim to have staked out a new position and to have thought about the substance of the issue more than anyone else,'' says James Fallows, whose book ''National Defense'' has popularized many of the same reforms Hart favors.

Hart's basic contention is that the military doesn't need more money as much as it needs to spend it differently. The Navy needs more smaller ships instead of a few expensive ones; a unit of soldiers will be more cohesive if it remains together; the ability to maneuver is more important than firepower: So goes the Hart litany.

His approach is not a knee-jerk liberal's opposition to weaponry, says Larry Smith, who was Hart's chief of staff for four years and who now works at the Kennedy School of Government at Harvard University. ''If he opposed a weapon system (such as the MX missile or the B-1 bomber), he had an alternative weapon system.''

His military reforms have rarely become law. For example, Hart has long sought small aircraft carriers, equipped for jets that take off vertically. The Pentagon has never bought the idea. But Mr. Smith argues that Hart's strategic ideas have gained acceptance.

He has also won respect from an unlikely corner, the dean of conservatism, Sen. Barry Goldwater, who praises Hart's efforts for the Navy. ''You can disagree with him politically, but I don't think I ever met a man in politics any more honest than he is, or any more moral,'' said the Arizona Republican in 1979, and he is said to stand by the remark today.

The success record has been mixed in the Senate, says Smith, who held a variety of Senate jobs during 14 years in government. He recalls that he was impressed from his first week with Hart by the wide range of Hart proposals that became public law. They ranged from a ban on binary nerve gas (later weakened by the House) to environmental legislation.

Two cases in the Hart record stand out, one a victory and the other a debacle:

* For Coloradans, one of Hart's big successes involves 700 ''wet-eye'' bombs of poisonous gas left over from World War II and stored next to Denver's airport. Efforts to force their removal had failed until 1980 when Hart took up the cause.

At that time, Smith recalls, the Hart staff was ''puzzling over this ridiculous thing of bombs at the end of a runway'' when Hart, from the corner of the room, casually announced, ''I'm going to write a law that will require them to be removed by a certain date.''

Hart wrote the law, it passed, and the bombs are gone.

''It was precisely positioned,'' Smith says of the Hart move. The senator had no need to cajole colleagues, but he knew the right lever to pull to make the law a ''fait accompli,'' recalls the former aide. He adds, ''Gary had a fine sense of the proper use of power.''

* If there is a Hart debacle, it came last year in his ill-fated filibuster against the MX missile. Not only did Congress approve the multiwarhead nuclear weapon, but Hart's performance displayed a lack of savvy about lining up allies for a fight.

Sen. John Tower (R) of Texas, leading backer of the MX, outfoxed him with a smooth parliamentary procedure. With Hart looking helplessly on, Senator Tower called up Hart's own amendment and moved to table it.

The filibuster bust would indicate that Hart has been somewhat isolated from his colleagues. But while he has few close social friends, he has found company for his concepts on Capitol Hill.

Many of his ideas run parallel with those of the House Democratic Caucus, which has recently devised lengthy Hart-like ''new ideas'' for the future.Several caucus members are said to be leaning toward his candidacy.

One staunch Hart ally is Rep. Martin Frost, a Texas Democrat. The two lawmakers formed a breakfast group of youngish, progressive Democrats who met monthly for more than two years with experts and leaders to talk about a variety of issues. Guests ranged from AFL-CIO president Lane Kirkland to economist Lester C. Thurow.

''I've never found him to be aloof,'' holds Representative Frost, who first made friends with Hart when the senator helped him raise funds for his election campaign in 1978. ''He's not your old-school politician. There're a lot of people in our generation - I'm 42 - who aren't your traditional 'hail fellow well met' politician.''

Among experts who have dealt with Hart, a common view is that he is thoughtful in ways uncommon among politicians.

''In the old days, the Democrats didn't worry about economic growth,'' Mr. Thurow says. The belief during the Lyndon Johnson days was that ''growth takes care of itself,'' says the Massachusetts Institute of Technology professor. ''The older Democrats still hold to that.'' He adds that Hart is ''one of the few (politicians) willing face up'' to the problem of creating full employment without inflation.