Boston — The strength of the US nuclear freeze movement's hold on its grass-roots support is about to be tested. A rival coalition is warning that the United States must not negotiate with the Soviet Union until it can do so from a position of strength.
The Coalition for Peace Through Strength, consisting of about 160 conservative, military, and other groups, says the public is being misled by those who are calling for the two superpowers to freeze their nuclear arms stockpiles at present levels. It is preparing to battle in town halls and state legislatures, as well as the US Congress, to reverse freeze resolutions that it says were the result of a propaganda campaign aimed at American voters.
''The other side is misinforming the US public,'' says Gen. J. Milnor Roberts , head of the Reserve Officers Association and cochairman of the ''Peace Through Strength'' coalition. The US must not commit itself to a ''simplistic'' nuclear weapons freeze, he says, because ''we are behind the Soviets in both conventional and strategic weapons.'' Instead, the coalition advocates better verification of Soviet strength and parity in nuclear strength before arms reduction agreements are negotiated, he says.
The general was one of a group that visited the White House Monday to urge President Reagan to release classified documents that reportedly would show how the US lags behind the USSR in military strength. If the public had had this information before last November's voting on various local freeze resolutions around the US, coalition members argue, such measures, which passed by an average margin of 60 to 40 percent, would have been defeated.
To publicize its position, the anti-freeze coalition, which includes the 2 million-member Veterans of Foreign Wars, staged a counter-rally in Washington Tuesday to activities being held to support freeze legislation now in the House. That measure was approved by the House Foreign Affairs Committee by a 27-9 vote Tuesday. Similar anti-freeze efforts are under way in US 50 cities, aimed at defeating local freeze resolutions and substituting ''Peace Through Strength'' measures, according to coalition members.
The coalition is promoting its resolution in Congress as an alternative to the nuclear freeze measure now in the House. The ''National Strategy of Peace Through Strength,'' expressed in eight general principles, calls for an effort ''to achieve overall military and technological superiority over the Soviet Union,'' and asks that no arms control agreement be negotiated that ''locks the US into a position of military inferiority.'' The coalition claims 233 congressmen and 55 senators have backed its resolution. But some of them also have expressed support for the freeze resolution.
As with the nuclear freeze legislation, the coalition's resolution would not require President Reagan to take any action. But passage of either the resolution, which was the subject of hearings last week in the House Foreign Affairs subcommittee, or the better-known freeze bill would be taken by their advocates as proof of widespread public support.
''All of us want peace, but a simple freeze on nuclear weapons won't guarantee peace,'' said Capt. Curtin R. Coleman, national president of the 23, 000-member Naval Reserve Association, one of the anti-freeze coalition members, just before the noon Washington rally Tuesday.
Passage of a freeze resolution would send the wrong signal, one of weakness not strength, to the Soviet Union, says Captain Coleman, and endanger the arms control negotiations now under way in Geneva. The Naval Reserve Association has urged its members around the country to rally in support of the ''Peace Through Strength'' measure.
Locally, the effort to spread the ''Peace Through Strength'' message can be waged by writing congressmen and senators, calling talk-in radio shows, sending articles to local newspapers, and debating freeze advocates in public forums, says Ted Temple, New England organizer for the Mid-America Conservative Political Action Committee (MACPAC), a sponsor of ''Peace Through Strength.''
At a local MACPAC gathering Monday, David S. Sullivan, a foreign affairs assistant to two GOP senators, told the group: ''It's up to people like you to get the word to (President) Reagan. . . . It's a problem of telling the people the facts. We have the facts on our side.''
''The Reagan administration is rapidly approaching a crossroads: [Is it] going to fight the freeze or not?'' Mr. Sullivan said.
Freeze opponents were encouraged by the conservative victory in the recent West German elections, arguing that it shows that the the forces of appeasement in the West, represented by the freeze movement, are not as strong as depicted in the news media.
In response to public demand for an end to the nuclear arms buildup, some freeze opponents are backing ''Project High Frontier'' as an alternative to negotiating with the Soviets under what they see as unfavorable conditions.
The ''High Frontier'' proposal would place nonnuclear antiballistic missiles on orbiting satellites. These missiles would shoot down Soviet intercontinental ballistic missiles before they could reach targets in the US. The system, it is argued, could provide at least a partial substitute for a further US nuclear buildup.
''Project High Frontier is the most exciting thing in defense thinking today in our country,'' says Sullivan. ''It provides the only unilateral defense program . . . that would assure us of a nonnuclear means of defending America.'' Unfortunately, he says, ''this isn't even being studied seriously in the Pentagon.''
''There's going to be a very interesting and exciting debate [on the freeze resolution] in the Congress in the next few weeks and months,'' says Sullivan. Countering with the ''Peace Through Strength'' resolution ''will be the first line of defense,'' he says, but ''we have several other procedural and legislative tricks up our sleeve.''