Congress returns from recess to plateful of unresolved issues

It's not yet summertime, but the working pace is easy on Capitol Hill, which at least in theory reopened for legislating this week after an Easter break. In fact, many of the legislators are still away, and major issues have been put off at least until next week.

Central America aid, an issue hot enough to make tempers boil over just before Congress left town, has moved temporarily to the back burner. Many lawmakers report finding little interest back home in revelations of a United States role in mining the harbors of the leftist country of Nicaragua.

Senate minority leader Robert C. Byrd (D) of West Virginia reported that his constituents were more interested in the economy than in Central America.

An ''urgent'' supplemental appropriations bill, including up to $62 million for military aid to help El Salvador fight its guerrilla war and $21 million for rebels in Nicaragua, still languishes in Congress. A House-Senate conference, which was due to work out a compromise two weeks ago, is not even meeting. Two of the principals, ranking Republican Rep. Silvio O. Conte and House Speaker Thomas P. O'Neill Jr. (D), both of Massachusetts, have been traveling overseas and will not return until next week.

Moreover, Rep. Michael D. Barnes (D) of Maryland, chairman of the House subcommittee on Latin America, has predicted that Congress will not act on Central America until after El Salvador elects a new president May 6. Many lawmakers are taking a wait-and-see approach, hoping that the elections will produce a moderate Salvadorean leader who will protect human rights.

The President bypassed Congress and sent El Salvador $32 million worth of equipment, but that action requires congressional funding within the next four months.

Mr. Reagan is also expected to seek more military funds for that nation.

Meanwhile, the Senate returns to its job of chipping away at the federal deficit by acting on an agreement already reached by Republican members and President Reagan. It would freeze nondefense discretionary spending at $137.8 billion for 1985, while permitting a 7 percent real growth rate in defense to $ 299 billion.

Both houses have already passed tax provisions to raise some $50 billion over three years in ways carefully crafted so as not to offend massive numbers of constituents in an election year. Differences in the House and Senate versions will have to be ironed out in a conference.

Senate majority leader Howard H. Baker Jr. (R) of Tennessee told reporters this week that he hopes to finish the deficit-reduction efforts before the Memorial Day recess in late May.

Such deficit-cutting attempts, which would shave only a portion of deficits ranging at $200 billion per year, may turn out to be the major achievement of the current Congress. The legislative year has so far been one of the least active in recent memory.

And with breaks for the two national conventions this summer and an Oct. 4 adjournment target, Congress will have little time to conduct major business, aside from funding and budgetary matters.

However, several controversial issues are still pending:

The MX missile. Having attempted to shoot it down and missing by only a handful of votes, the opponents will aim again at the $20 billion nuclear weapon. This time they will focus on the defense authorization bill as they seek to remove all funds for MX construction, including $3.1 billion for 1985.

''We think the vote is a tossup,'' says Nick Koskores, an aide to Rep. Nick Mavroules (D) of Massachusetts, one of the leading MX foes. The opponents will once again attack the basing system, which is in existing missile silos, as vulnerable.

This time they will not have to contend with the emotions that surrounded the vote last fall, which was held not long after the Soviets shot down the South Korean airliner.

Moreover, the opponents hope to win over some moderates by pointing to the stalled arms negotiations with the Soviets.

Immigration reform. Due to arrive on the House floor in May, the bill would enact landmark reforms in the handling of illegal immigrants.

Many already in residence in the US would be legalized, but the bill would attempt to curb the inflow of foreigners by imposing sanctions against employers who hire them. A similar bill has already passed the Senate.

The proposal is hitting intense opposition from Hispanic members of the House who charge it will result in discrimination against legal residents who look or sound foreign.

One House leadership aide predicts a rocky road for the reform bill. ''There is no passionate support for the bill,'' says Christopher J. Matthews, an assistant to the House speaker.

Natural gas deregulation. Although a major change late in an election year seems unlikely for natural gas policy, the House Energy and Commerce Committee has proposed a ''pro-consumer'' bill that could go to the House floor in July.