Washington — Two major national security debates make return engagements this week, as the Democratic House challenges President Reagan on Central America and the MX missile.
After more than a month of relative quiet, congressional critics of covert aid to rebels in Central America are speaking out again. Amid news reports of increased United States aid to guerrilla forces in Marxist Nicaragua, the House plans a rare secret session Tuesday to hear classified information about Central America. Later it will consider whether to cut off those funds.
The White House has already acted to blunt criticism by announcing a bipartisan commission to study US policy in the region.
Meanwhile, the Reagan-backed MX missile, which seemed to be on track in May when both Houses voted for it, is hitting snags. Although it has the votes for the missile, the Republican Senate leadership is having to beat back delaying tactics of opponents on a bill funding MX construction. House opponents have been working hard to delete the money during a scheduled vote on Wednesday.
Neither side has victory in the palm of its hand in these controversies.
''I think it's going to be a very close vote,'' House Speaker Thomas P. O'Neill Jr. (D) of Massachusetts says of a proposed bill to cut off covert aid to antigovernment fighters in Nicaragua. The vote will not come until next week, however, giving the administration more time for its intense lobbying campaign, and allowing opponents more time to make their case.
Democrats, who are gearing up for a major push on the Central America question, are aiming first at the covert aid, which appears to be the most vulnerable of the Reagan policies on Central America. It's the one subject on which Democrats are most united.
Rep. Bill Alexander of Arkansas, the deputy Democratic whip, fired one of the early shots, charging that ''this administration is pursuing a policy which I characterize as simple-minded deception of the American people and Congress.'' The Reagan administration is ''using hidden money to support a secret war in Nicaragua,'' he said.
At issue over the covert aid to Nicaraguan fighters is whether the administration has broken a 1981 law forbidding US aid to overthrow a foreign government. One leadership aide called it an ''institutional issue'' in which the President ignored the law passed by the House, so it must object.
But not all Democrats see the issue in such black-and-white terms. The No. 2 man in the House leadership, majority leader Jim Wright of Texas, has been meeting with the White House and Republicans to try to reach a compromise.
Another Democrat, Rep. Dante B. Fascell of Florida, a member of the House Foreign Affairs Committee, has forged a compromise on Central America in the past, and he's trying again. He opposes the bill sponsored by Rep. Edward P. Boland (D) of Massachusetts to cut off funds for covert activity. ''It's a symbolic vote,'' he said, which would have little chance of becoming law.
This new round of Central America debate will determine if Democrats are skittish about perhaps being blamed for losing the region to the communists. Representative Fascell denied that such a ''red-scare threat'' motivates him. But an administration critic countered, ''When the White House puts out the 'red scare' around here, a lot of people run for cover.''
A Republican leadership aide pointed out that the Democrats are on dangerous ground in the dispute. ''There is a great risk in aligning yourself with presidential policies . . . should those policies fail,'' he said. ''There is equal risk in refusing to compromise and then being responsible for the default of the American position in Latin America.''
Rep. C.W. Bill Young (R) of Florida said he was ''confident'' that he can win votes for a compromise plan. It would require the Nicaraguan government to stop interfering with its neighbors in return for ending US aid to rebels.
Meanwhile, the bipartisan compromise on the MX will have a thorough testing Wednesday as the House votes on the Defense Department authorization bill. Rep. Les Aspin (D) of Wisconsin, a liberal who helped the Reagan administration pass the MX in May, told a breakfast meeting of reporters that it would be a ''very, very tough vote.''