A couple of weeks ago, a conservative administration was disregarding the importance of law, domestic as well as international, in pressing Congress to provide military aid to the Nacaraguan contras. It lost.

This week a liberal Congress seems to be disregarding history in pressing the executive to provide military aid to the noncommunist forces in Cambodia. It, too, should lose.

We ought to know well by now the liabilities of committing U.S. military prestige in land wars in Asia and ought not to head down that road again without a consensus that such a course of action is in our national interest.

Interventionism is an idea whose time on the clock of history may not precisely have passed. But problems of law and morality aside, there are ever fewer cases where an interventionist foreign policy has proven effective.

It is not enough to conclude that a cause is just -- which support of the democratic forces in Cambodia patently is. An assessment must also be made that U.S. involvement is of such a nature as to advance just goals and that constitutional procedures and precedents are followed. Ironically, in Nicaragua we have today intervention without congressional sanction; in Cambodia tomorrow we may witness intervention without executive initiative.

In this context the case for initiating a military aid package to democratic resistance forces in Cambodia is profoundly uncompelling.

The American taxpayer is not prepared to underwrite a new military venture in Indochina without a well-defined national interest carrying the broadest support of the executive, Congress and the public at large.

While the initial $5 million funding level may seem a pittance to geopolitical strategists, it will only raise unrealistic expectations o a U.S. commitment to provide aid indefinitely and to do so at increasing levels. If we are not in it for the long haul and at a funding level that will not make a difference, we ought not to hold out false promise to the courageous people whose lives we are jeopardizing.

Moreover, the need for U.S. military aid has not been established. The weapons requirements of the noncommunist resistance are modest and well within the means of the nations in the region. The administration has in fact notified Congress that it is neither necessary nor appropriate for the United States to provide military aid at this time and that the democratic resistance has been provided all the weapons it can currently absorb. The major needs for the resistance are improvements in leadership, discipline and training -- not arms.

While $5 million of publicly committed funds is not nearly enough to enhance significantly the ability of the Cambodian resistance to counter the Vietnamese army, the world's third largest, it is more than enough to taint their operations as a U.S. military reengagement in Indochina and, like it or not, change the character of this regional struggle.

It is also more than enough money to invest the national reputation and military prestige of our country in an operation over which we have virtually no control.

If perceptions develop around the world of a Vietnam-revisited syndrome, international support for democratic forces in Cambodia will almost certainly be undermined. Cambodians should not be treated as pawns in superpower conflicts that they neither understand nor control.

It is simply fantasy to believe the fledgling democratic resistance to the Vietnamese occupation will not be dominated by Pol Pot and the Khmer Rouge, with which it is in a tactical alliance. If the president's effort to seek reconciliation with the German people at Bitburg offends the sensitivities of millions of Americans, what will be the view of Asians when U.S. policy implies indirect alliance with today's SS?

Yesteryear's war criminals are alive and well in Southeast Asia, and despite high-minded desires to the contrary, there is no way at this time for the democratic resistance to avoid complicity with Khmer Rouge atrocities when their forces are so integrally allied.

Finally, and most tragically, rather than providing further pressure on the Vietnamese to negotiate, Americanizing the conflict could serve as an invitation to them to perpetrate a new genocide -- of the very people with whom we sympathize most.

It is time for Congress to apply restraint before a domino decision-making process is initiated. The killing fields of Southeast Asia should produce crops again, not new cemeteries.