IN its 13-year history from proposal to the threshold of procurement, the MX missile has escaped all direct political shots to kill it. By shuttling it to various basing modes, by calling out bipartisan commissions to defend it, the MX has survived to today's expected vote in the House.
The case for the MX has no permanently hardened silo, however.
The argument of the Reagan administration, its latest defender - that the MX, dubbed ''peacemaker,'' was a bargaining chip to gain concessions from the Soviets at the bargaining table - looks frail in the deepening chill in US-Soviet relations. Even the Scowcroft commission had defended the MX largely in terms of deterrence and arms control.
No talks, no chip. By taking such a position and withholding funds for building the MX, the House would be putting the program's leverage as much on the Reagan administration to pursue talks as on the Soviets to respond.
Funds for research and development, for readying the MX for production, would be maintained. Even should the House vote to cut off procurement, the issue would be taken up again later this year in a House-Senate conference.
The compromise by Rep. Les Aspin - calling for 15 missiles instead of 40, and holding up production for six months to see whether the Soviets come to the table, and another six months to see how the talks go - has much to commend it. Congressman Aspin's argument is that the Soviets should not be rewarded for their walkout. His proposal acknowledges that the United States and Soviet Union have their own domestic political equilibrium to establish in the months ahead.
Waiting until 1985 to resolve the MX's fate recognizes that the United States has to settle on its own approach to arms talks this summer and fall in the election campaign. The three Democratic candidates oppose the MX. Walter Mondale has been lobbying congressmen to vote against it. He hit the issue in his opening volley from San Francisco yesterday. The vote in Congress on the MX may well tell how much of a constituency remains for the Reagan administration's ''peace through strength'' campaign appeal.
In 1985 a new four-year chapter begins, from the US side, in attempting to find the best balance between America's arms configuration and its diplomatic approach to the Soviet Union. This is the obvious fact, whether the Democrats or the Republicans win the White House.
Despite the plain evidence that the Kremlin is dousing the Reagan administration with every cold pitcher of water it can get its hands on, some US arms control analysts claim a deal could be struck this year if the White House were willing to pay the Soviets' price - which so far Mr. Reagan is not. From the Kremlin's point of view, NATO's midrange Pershing IIs and cruise missiles in Europe are the critical weapons, not the MX.
Keying the MX's fate to a Soviet response in the near term poses problems of its own. The Soviets at best are playing a very enigmatic game. The health of the third Soviet leader in two years is in question.
Some analysts claim that domestic politics may have taken over in the Soviet Union, at the same time the US embassy has been cut out of the picture and insights on Kremlin thinking have grown dim. What the Soviets are up to in Afghanistan, the Caribbean, Southeast Asia, Africa, and elsewhere - the timing and scope of it all - is puzzling.
Whether a whole new and brighter era will open in US-Soviet relations in 1985 , or whether the six-year downtrend that began during the Carter administration will continue, must be decided.
The MX can wait for that.