LATER THIS WEEK, when President Reagan and his political advisors carefully scrutinize the state by state results form today's midterm elections, one race they are likely to ignore is the senatorial contest in Connecticut between Republican incumbent Lowell Weicker and Democratic Rep. Toby Moffett, Weicker, fighting for his third stint in Washington, is considered too liberal to serve as an accurate barometer for the President's policies.

If anyone deserves the maverick lable, it's Weicker. In Congress, he has voted against the GOP line as often as not, earning the wrath of the Republican hierarchy. On issues like busing, which he favors, and school prayer, which he opposes, Weicker has adhered to traditionally Democratic positions. And when Weicker stands alone among his party peers, he by no means constitutes a silent majority. "The problem with Lowell," says one Republican official in New Haven, "is that he makes too much goddamn noise."

This year, though, Weicker is caught in the middle. With Moffett, a liberal's liberal, on the left and Conservative Party candidate Lucien DiFazio on the right, the middle of the road is a delicate line. Being moderate, Weicker says, used to mean fence-sitting. Now it means "getting it from both sides."

But to win in Connecticut--where 40 percent of the electorate is Democratic, 34 percent unaffiliated and only 26 percent Republican--Weicker must attract liberals. So he has emphasized issues on which he and Moffett agree in the hope of siphoning off some Democratic and Independent votes. Moffett has countered by stressing the gaps in Weicker's image as a moderate--such as his support of several conservative bills in Congress, including Reagan's budgets, defense spending and tax cuts.

"We differ on energy, on defense, on the economy," Moffett has said. "I think that is finally coming through."

So far, Moffett's strategy has had mixed results. Some liberal groups, like the National Organization for Women, have endorsed both candidates. Others, such as the AFL-CIO, are supporting neither. The Democrat clearly has favor with Blacks and students, two of Connecticut's significant constituent groups. But at the same time, he cannot risk placing himself too much to Weicker's left. A former disciple of consumer advocate Ralph Nader, Moffett has had problems in the past with his own party's bosses, and, against a surprisingly well-funded Weicker, he needs all the support he can get.

IN THIS RACE at least, the little matter of who is beating whom says more about statistical analysis than it does about state politics. During the first week in October, a New York Times poll showed Moffett ahead by five percentage points. The same week, a University of Connecticut-Hartford Courant canvass had Weicker up by 16 points. Since then, another Times poll has put Weicker in the lead by two points or sixteen points, depending on the order the polling questions were put to voters.

As such numbers may or may not show, the choice between a very independent Republican and a liberal Democrat will not be an easy one for voters. During his two terms, Weicker has built a largely positive reputation among voters used to seeing politicians toe the line. His provocative and intelligent questioning of administration officials during the Watergate hearings merits particular praise. In the end, though, Moffett is even more attractive. As a representative, he consistently fought for liberal causes, proving himself to be an effective and articulate Democratic spokesman. As a senator, he will continue to try to protect shut is left of social services and battle excessive defense spending.

Another compelling reason to vote Moffett is the possibility his election will give Democrats control of the Senator. They need a net gain of five seats to be able to appoint and chair committees now run by Republicans. A Moffett victory could mean a judiciary Committee headed by Ted Kennedy instead of Strom Thurmond, and a more visible senator in a Democratic party that sorely needs new leaders.