Washington — Eight years after the last American serviceman left Indochina, there is new hope for more than 500 families of those missing during the 10-year air war over Laos.
The People's Democratic Republic of Laos and the United States have moved from negotiations to action in setting up joint investigations of crash sites. Between Dec. 19 and 22, the Laotian government played host to staff of the Joint Casualty Resolution Center (JCRC), the Honolulu-based US office charged with resolving the issue of servicemen missing in Southeast Asia.
The JCRC team and Laotian counterparts made a ''feasibility study'' at a crash site in southern Laos to determine what equipment is needed for an excavation and whether there are unexploded bombs in the area. Laotian officials also turned over some unidentified remains, which the team has brought back to the US for identification. If all goes well, the first MIA crash site excavation could occur early in 1984.
The December visit signals not only a crucial breakthrough in searches for servicemen missing in action (MIAs) but also a new phase in Lao-US relations. As a Laotian diplomat commented, ''Negotiations are moving quickly now from the theoretical to the practical.''
After two years of negotiations - sometimes stalled by outside events - State Department officials seemed pleasantly surprised by the unexpected Laotian offer.
In 1981, the Reagan administration and the Laotian government began an old-fashioned gesture-for-gesture diplomatic scenario. Now with the 1984 election nearing, President Reagan appears to be pressing for results on past electoral promises about MIAs.
Laos has its own reason for improved relations with the US. ''Our policy is to make friends not enemies with all superpowers,'' a Laotian official says. Specifically the Laotians want congressional restrictions on direct US aid lifted. The Reagan administration has made access to crash sites a condition for asking Congress to consider aid to Laos.
Much of the postwar ideological mudslinging between the two nations has subsided in recent months.
However, as negotiations move into the ''practical phase,'' the two governments are sensitive to embarrassing sideshows by independent mudslingers and soldiers of fortune. Officials on both sides recall the misadventures of former Green Beret Bo Gritz. Earlier this year, just prior to a crucial JCRC-Laotian negotiating session, Gritz boasted to the press about his illegal forays into Laos in search of prisoners of war.
A source close to those negotiations claims Gritz ''almost destroyed two years of delicate diplomacy.'' At a minimum all agree Gritz delayed joint crash site investigations by 10 months. It took three high-ranking meetings in New York and three in Vientiane to bring negotiations back to concrete actions.
Currently the State Department is worried about public reaction to ''Uncommon Valor,'' a Hollywood dramatization of Gritz-style raids into Laos. The State Department discouraged release of the film, fearing it might spur more illegal forays.