Like James Stewart in the award-winning 1939 film, ``Mr. Smith Goes to Washington,'' Belgian Prime Minister Wilfried Martens goes to the US capital this week. But he is not likely to win any Oscars from the Reagan administration on this official visit, which is to include a meeting with the President, for Belgium's performance on foreign-policy issues over the past year. Relations between the United States and Belgium -- traditionally one of Washington's closest NATO allies -- have been strained in recent months.
Last year, the US vehemently opposed the proposed sale by Belgium of certain high-tech machinery to the Soviet Union, which some officials said could be used to manufacture launchers for SS-20 missiles. Earlier, Belgium had declared itself in line to receive $1 billion in contracts to help Libya build its first nuclear power plant despite US objections that the know-how could help Libyan leader Muammar Qad-dafi make an atomic bomb.
Both deals appear to have been shelved. That has pleased the White House. Yet the problem that in the long run could be the most divisive remains.
Under a NATO rearmament plan initialed in 1979, 48 US-made cruise missiles are due to be deployed on Belgian territory beginning in March. But last month, under pressure from antinuclear activists and some key politicians, the Belgian government put off deciding whether to give the green light to deployment until after Mr. Martens' visit to Washington today.
There is talk here that the Belgians hope to delay the deployment decision until after national elections scheduled for next December. Washington would understand this, officials close to Belgium's center-right government say, because deployment before the elections would provide a much-needed public relations gift for the opposition Socialists, who strongly oppose deployment.
Last week after briefing Martens on the Geneva talks between US Secretary of State George Shultz and Soviet Foreign Minister Andrei Gromyko earlier in the week, the Reagan administration's special envoy on arms control, Paul H. Nitze, was asked about the Belgian situation. He said that alliance ``solidarity'' was crucial.
In Brussels last month, Mr. Shultz told reporters that the failure of the Belgian government to go ahead with deployment on schedule along with the other countries involved in the NATO plan -- the United Kingdom, West Germany, Italy, and the Netherlands -- could be harmful for the US-Soviet arms talks.
How sensitive the deployment issue has become here was underscored last week when a Belgian newspaper reported that the cruise missiles would begin arriving in Belgium for eventual deployment at a military base at Florennes, south of Brussels, between Jan. 15 and 31.
Opposition politicians and antinuclear activists greeted the disclosure with anger, forcing the Defense Ministry to deny the report. There will be no ``automatic'' deployment of cruise missiles in Belgium, Defense Minister Alfred Vreven said. No missiles will be allowed into the country without the ``explicit approval'' of the Belgian government, he insisted.
Some analysts say it may be politically impossible for the Martens government to give the green light to deployment. Doing so before the elections could risk the collapse of the staunchly pro-US, center-right coalition government, these analysts argue. Not surprisingly, this view is supported by activists in Belgium's increasingly influential peace movement.
``There has been an evolution in public opinion over the past year,'' according to Pierre Galand, who heads one of the country's largest antinuclear organizations.
Citing polls showing up to 75 percent of Belgians opposed to deployment, he attributes this ``evolution'' in part to the Dutch government's decision last June to postpone until November of this year its final decision on deployment of 48 cruise missiles in the Netherlands.
For his part, Martens was unusually tight-lipped before his trip to Washington. Asked Friday to venture a comment on the Shultz-Gromyko talks in Geneva, he replied, ``I'll have nothing to say until after I meet with President Reagan.''