President Reagan has outlined a communist threat to United States security in Central America that is taken seriously by the House Intelligence Committee. Now the committee has voted for means to meet the threat without risking counterproductive CIA support of military operations in Nicaragua. The committee calls for $80 million in open and aboveboard aid to help Central American countries themselves prevent a flow of arms intended to overthrow any government in the region.
It is the flow of such arms through Nicaragua to El Salvador that the present US covert activities are designed to ''interdict.'' Covert funds are prohibited by law from being used to overthrow the government of Nicaragua. Congress's concern is that, whatever the administration's limited intent, covert aid is going to groups of former dictator Somoza's supporters and others who do want to overthrow the Nicaraguan government.
Some supporters of the administration's covert activities note that Congress earlier rejected an amendment that would have specifically prohibited aid to groups intending the overthrow of the Nicaraguan government. But to aid such groups violates the spirit of the existing amendment prohibiting the use of funds for a US purpose of overthrowing that government.
This week's vote by the House Intelligence Committee, with all the Republican members in opposition, is only a first step. But it stakes out a clear position for debate and one that could save the US from current charges that it is violating international law against interventionism. The committee rules out expenditures by any US intelligence agency that would support directly or indirectly any military or paramilitary operations in Nicaragua.
The United States has had enough trouble with covert operations in the past to know that the burden of proof is on the side of showing that they do more good than harm. So far this has not been shown in Central America, and here is one ''pragmatic'' reason for Congress to be concerned. But covert operations are also fundamentally at odds with American democracy, and here is another reason for congressional concern that such actions not damage democracy in the name of protecting its security.