Why '85 defense bill is stalled in Congress; Election-year politics, arms-control concerns put measure on hold

While virtually agreeing about the size of the Pentagon's budget, members of Congress are at an impasse over defense spending for 1985. And because this is a presidential election year, the political arm-wrestling is of Olympic proportions.

The issue is arms control and the next steps in the development and deployment of several weapons of major strategic importance: those designed to fight in space and a new generation of nuclear missiles.

Once again, the controversial MX intercontinental ballistic missile is a key stumbling block to passage of the 1985 defense authorization bill. The Democratically-controlled House wants to tie MX funding to a potential congressional veto on the missile next spring. House members of a defense spending conference committee also want to delay testing of a new anti-satellite (ASAT) rocket until next year.

Republicans in the Senate are just as adamant in their opposition to what they see as an attempt to tie the Reagan administration's hands on two important military systems. They accuse House Speaker Thomas P. O'Neill (D) of Massachusetts of sabotaging the conference committee's efforts in line with Democratic Party presidential platform positions.

The MX and ASAT issues were hot political items long before the 1984 campaign began. Both have only narrowly survived legislative challenges in the past. There is no doubt, however, that the quadrennial election effort has more sharply drawn the battle lines.

A large bipartisan - but mostly Democratic - group of former government officials (including intelligence, State, and Defense Department officials, arms controllers, military officers, and lawmakers) have organized to fight the extension of the arms race into space and ''save'' the Anti-Ballistic Missile Treaty of 1972.

Nuclear freeze advocates also are very active. They raised a quarter of a million dollars at parties in 35 states over the weekend and intend to work for friendly members on Capitol Hill and the Mondale-Ferraro team.

All of this is behind the Reagan administration's desire to have an arms control session with the Soviet Union in Vienna before the November election that would include both space weapons and nuclear missiles.

The administration contends that both the MX and the new ASAT weapon are necessary responses to Soviet weapons, both as deterrents to war and as bargaining chips for arms control. But many other experts disagree.

William Colby, former director of the Central Intelligence Agency, calls the MX ''useless and dangerous.''

Over breakfast with a small group of reporters Wednesday, he said the multiwarhead missile does not add to US military strength because it will be deployed in vulnerable fixed silos. And he said it is dangerously destabilizing because it is so accurate and powerful that it could only be viewed by Moscow as a first-strike weapon and not merely retaliatory.

The Pentagon already has approval for 21 of the planned 100 missiles to be deployed (plus 20 test MXs). As far as being a possible arms-control bargaining chip, Mr. Colby warns that ''you get the MX in the holes out there, and our military isn't going to give them away.''

The former CIA chief favors a mutual, verifiable freeze on the testing and deployment of nuclear weapons. ''I don't want a 'sweetness and light' freeze treaty,'' he says. ''I want one carefully drawn.'' Colby is also one of 58 former senior officials cosponsoring the ''National Campaign to Save the ABM Treaty.''

The group contends that recent developments in Soviet and US weaponry - and especially technological advances being made by both sides - threaten to undermine one of the few solid arms control agreements ever successfully concluded. Moves by either superpower to fashion an active defense against nuclear attack would only spur increased deployment of nuclear warheads and thereby undercut deterrence and strategic stability, these experts argue.

It is just such questions that have thrown a wrench into the spokes of the congressional defense budget process.

At the moment, it appears unlikely that the House and Senate conferees will agree on a defense authorization bill before they recess for the Republican convention this month and then begin their own active campaigning. This means that the Pentagon would have to operate under a continuing resolution (with spending levels frozen at 1984 levels) and face more flak when the generally less-friendly appropriations committees begin their work on defense spending later this year.