Shifting US strategic defenses to the high ground of space is fast becoming a major political issue here and abroad. It spreads from internal Pentagon machinations through domestic lobbying and activism to allied and superpower relations.
Notwithstanding President Reagan's controversial ''Star Wars'' speech last spring calling for new ways to defend against nuclear attack, there are forces within the US armed services resisting the antisatellite weapons and systems to intercept enemy nuclear warheads now being developed by the Defense Department.
Those close to the scene say this includes strong doubts about the technology and strategies involved, as well as the desire to protect favored programs that could be undercut by such a significant shift.
''Frankly, the services are not behind this thing,'' says Robert Bowman, president of the Institute for Space and Security Studies. ''It's being crammed down their throats.'' Dr. Bowman is a retired lieutenant colonel who headed the Air Force Office of Advanced Space Programs Development, was a space industry executive, and now opposes space-based strategic defenses.
''The hard-core opposition, sad to say, is in the bureaucracy,'' agrees retired Air Force Brig. Gen. Robert Richardson, deputy director of High Frontier , a group favoring new strategic defense systems.
In recent months, groups organized for and against space-based weapons have sprouted, including a political action committee that has raised several hundred thousand dollars to defeat incumbents opposed to the militarization of space.
Among those targeted by American Space Frontiers are Sen. Charles H. Percy (R) of Illinois and Rep. James Jones (D) of Oklahoma.
Another new group, the Institute for Security and Cooperation in Outer Space (founded by a former defense industry official) is arming peace and antinuclear groups with information handbooks to make their case.
Lawmakers favoring a ban on weapons in space have grown to more than 120, and hearings on strategic defenses are to be held in the Senate next week. Says a congressional analyst working in this area: ''This is going to be one of the top arms control issues next year.''
Meanwhile, Reagan administration officials are proceeding warily through what could become a domestic political minefield. Conservatives are pressing them to reveal more intelligence data showing that Moscow is violating the Anti-Ballistic Missile (ABM) Treaty by building a massive new radar system.
To spotlight this would no doubt bring a sharp response from more liberal critics who charge that the President's ''Star Wars'' proposal also would violate this treaty.
Officials here are carefully weighing their next step since Soviet leader Yuri Andropov dropped from sight shortly after he proposed a ban on antisatellite weapons last summer and the Soviet Union had offered a space treaty at the United Nations. This is one reason the testing of a US antisatellite missile has been delayed.
US Defense Secretary Caspar W. Weinberger is in Europe this week, and one of his important messages to allies there is that this country does not intend to abandon its friends and become a ''fortress America'' behind a wall of strategic defenses.
The administration was encouraged recently to have a gathering of 200 parliamentarians from the NATO countries approve a resolution urging the United States to continue developing a space-based ballistic missile defense system. Sources here expect the President within the next month or so to give another major address on the subject.
The administration in any case is quietly but determinedly proceeding toward development of a system of strategic defenses the President says could ''render impotent'' ballistic-missile warheads and thus lessen the likelihood of nuclear war.
The Pentagon's proposed 1985 budget will include nearly $2 billion for missile defense systems, including particle-beam, microwave, and high-energy-laser technology.
The Air Force and Navy have recently used the Defense Department's Airborne Laser Laboratory to shoot down air-to-air missiles and target drones.
The Defense Department is considering a proposal to use the space shuttle to test means of defending US satellites against attack. If the recommendation of the Joint Chiefs of Staff is followed (as expected), a new, unified space command will be created to centralize the increasing militarization of space.
For the moment, most of the official effort in this area is concentrated in research and development. Promoters of space-based defenses say they fear the administration will ''R&D it to death.'' They insist that such a system need not be ''leak proof'' to deter a nuclear attack.
''At minimum, strategic defense would enhance deterrence by introducing significant uncertainties in the minds of Soviet planners about the success of a Soviet first strike,'' says Robert Foelber, a strategic weapons analyst with the Heritage Foundation.
Former Air Force space specialist Robert Bowman counters that such weapons ''would be likely to bring on the war which we do not want and could not survive.'' A ''Star Wars'' defense, he says, would be very costly, violate existing arms control treaties, and most likely be overwhelmed by a foe's launching more warheads.
As the 1984 political campaign heats up, such arguments are sure to grow louder.