American officials this week are making a special pitch to European allies on the importance of strategic and theater nuclear forces. At the semi-annual meeting of the NATO defense ministers' Nuclear Planning Group, being held this time in Turkey, the United States will:
* Urge that Pershing II and ground-launched cruise missiles be deployed in Europe as scheduled.
* Argue that United States plans for ballistic-missile defenses and antisatellite weapons are not a part of any ''fortress America'' move or the first steps in a new ''Star Wars'' arms race.
* Try to demonstrate US steadfastness on the administration's plans for strategic modernization (MX, B-1, et al.) in the face of congressional grumbling.
As usual, most business will center on briefings by Caspar W. Weinberger and other US defense officials.
When Secretary Weinberger met with his fellow defense ministers six months ago, he was upbeat about the prospects for arms control efforts in Geneva. Since then, there has been absolutely no progress on either strategic or intermediate-range nuclear arms talks. And in Turkey, US officials will be warning their European counterparts that verification in particular remains an extremely difficult arms control challenge, and that it could be even more troublesome as the two sides talk about conventional forces and chemical weapons.
But Weinberger's toughest - and certainly most sensitive - job may come on his way to the conference, when he stops off in the Netherlands.
The Dutch parliament is debating whether to go ahead with the planned deployment of 48 cruise missiles there, that country's allotment of the 572 US-built missiles scheduled to be deployed in five NATO countries. And the vote in June is expected to be close.
Senior Pentagon officials insist that the Weinberger visit to The Hague is not meant to be intrusive and is merely coincidental, since the Netherlands is one of only two NATO countries he had not yet visited. But Weinberger is sure to be pressed on arms control and nuclear matters by Dutch parliamentarians. And some observers here suggest that the US defense secretary's presence alone could play into the hands of opponents of missile deployment.
US officials are willing to risk this, however, since they see allied unity at this time as particularly important, especially in light of stalled nuclear arms talks and increased frostiness between Washington and Moscow. The idea here is to head off any new surge of allied uneasiness that could undermine NATO nuclear-weapon deployments in response to new Soviet SS-20 missiles aimed at Western Europe.
''The secretary will stress that any Dutch decision not to deploy will deal a severe and possibly fatal blow to the hopes for renewed negotiations,'' said a senior defense official. ''The Soviets will not return (to Geneva) if they think the tide is flowing in their direction.''
It was just a year ago - when Weinberger was in Portugal for a similar nuclear planning group meeting - that President Reagan announced his controversial space-based ballistic missile defense (''Star Wars'') proposal. Weinberger will stress to the Europeans that such a system could eventually protect Europe as well as the United States, and that it could enhance arms control.
Critics fault the Reagan administration for foot-dragging on arms control. They point to the insistence by some top Pentagon officials on deep cuts in Soviet missile forces and very strict verification measures. It will be argued in Turkey that politics - the presidential campaign in the US, and succession turmoil in the Kremlin - are the cause of arms control doldrums, not US intransigence.
It will be pointed out that there is thus a parallel between the current situation in superpower relations and the attempt by the Soviet Union a year ago to influence West German elections by stirring up antinuclear sentiment.
That earlier effort by the Soviets failed, and the 1979 NATO decision to deploy new missiles in the absence of an arms control agreement became fact when the first missiles were stationed in Europe late last year. The Netherlands has always been seen here as the shakiest of the nations scheduled for deployment (West Germany, Britain, Italy, and Belgium are the others).
While the missiles are not scheduled to move into the Netherlands for some time, site preparations and construction must begin this summer for timetables to be met. This will be the focus of this summer's vote in the Dutch parliament.
In addition to allied unity, Secretary Weinberger will be stressing that the Western alliance will be withdrawing many more nuclear warheads (mostly older, short-range battlefield weapons) than the 572 new ones. Since the Pershings and cruises will now be able to reach Soviet soil (and thus are seen as more threatening to Moscow), this may not placate Dutch concerns.