In the congressional struggle over foreign aid last year, Rep. Jonathan B. Bingham (D-N.Y.) helped to fashion the compromise by which U.S. military assistance was sent to El Salvador.

He believed that the compromise pinned the Reagan administration down. Before shipping arms to the Central American nation, the administration had to determine that certain improvements were being made, among them progress in protecting human rights.

This year Bingham is in no mood to be cooperative. The administration's certification of human rights progress in El Salvador, he says, "was based on a denial of the facts. My impression is that they were just determined to go ahead with aid and find the facts as they wanted them to be."

Instead of designing intricately worded compromises, Bingham now favors cutting off all aid to El Salvador.

That shift, by an influential House Foreign Affairs Committee member, is indicative of the broad opposition the administration faces this year in trying to push through a new foreign aid bill loaded with military aid for a number of countries whose governments are unpopular with some.

Congressional Democrats will try to tighten the restraints on aid-giving to authoritarian governments. There is fairly wide agreement that the ones used last year were not tight enough.

In the cases of Chile, El Salvador, Guatemala and perhaps Argentina, Democrats and a few Republican allies will try to wrap the administration in language binding enough to stop or slow the pace of military assistance.

The opposition is in part fiscally inspired. House Foreign Affairs Chairman Clement J. Zablocki (D-Wis.) said passage of a foreign aid bill will be difficult in an election year "amid a slumping economy at home, after we just voted for a global aid bill in December."

A key Republican, Rep. Silvio O. Conte (Mass.), said he thought the chances nearly hopeless. "This would be a tough one--I think the toughest one in my 24 years in Congress. It's hard to justify a $9 billion foreign aid bill when they're cutting down in the health programs here."

Passing foreign aid legislation in an election year is always chancy. Many members thought the exhausting battle last year got it all out of the way for two years and are chagrined to see the administration back asking for more in both fiscal 1982 and 1983.

The fragile alliance of liberals and conservatives that finally produced the compromise last fall and winter may not hold up. It was based on a delicate balancing of economic aid, which liberals favor, and military assistance, which conservatives find appealing.

The administration's requests for fiscal 1983 are weighted with military hardware in the form of huge increases in foreign military sales credits.

Conte's quick analysis of administration requests shows that "security assistance" would rise by 35 percent while economic aid rises by only 5 percent, an abrupt departure from past budgets in which economic aid either equaled or exceeded arms assistance.

Beyond the fiscal roadblocks lies a minefield of congressional objections based on the sheer unpopularity of many of the governments Reagan proposes to aid. Plans for military aid to the likes of Chile, El Salvador and Guatemala create a wide gulf between congressional Democrats and the White House.

Unable to muster the votes to prohibit aid to several countries last year, Democrats tried a variety of strategies for restraining the president. The one most commonly used was a requirement that the president certify to Congress that a recipient country is improving human rights protections, curbing its military's excesses or making other democratic and social reforms.

The congressional campaign this year will endeavor to tighten those certifications, either with a congressional veto or through stricter language that would make it more difficult for Reagan simply to certify a change and proceed to distribute arms.

In the most volatile case, El Salvador, the battle lines are forming around a proposal by several Senate and House Democrats who will insist that the civilian-military junta promise "unconditional negotiations" with the guerrilla forces after the March 28 elections.

The Reagan administration and the junta of Jose Napoleon Duarte oppose "unconditional" talks because they say the guerrilla factions are interested only in dividing up power and would use such negotiations for that purpose.

"The lesson of the certification process last year is that if it is to change or affect policy, it must be drawn with iron-clad tightness or with a congressional veto built in," said Rep. Stephen J. Solarz (D-N.Y.) The one pushed this year, he said, will require the president to certify that the junta has accepted the concept of "negotiations without predetermination."

A report last week by Sens. Patrick J. Leahy (D-Vt.) and Claiborne Pell (D-R.I.) endorsed "unconditional negotiations" as correct U.S. policy. They had visited El Salvador recently and concluded that a military solution was nowhere in sight.

El Salvador will be the principal battleground in Congress because of the growing U.S. commitment of arms and money. About $100 million of the administration's new $350 million Caribbean basin initiative would go to El Salvador, and so would about $35 million of the $60 million fiscal 1982 supplemental military aid being proposed.

Included in the administration's fiscal 1983 security assistance program is $166 million for El Salvador, more than a third of it for foreign military sales credits and guaranteed loans.

The administration's plan to revive in a small way the once-abandoned military aid to Chile also is expected to provoke strong Democratic opposition in both houses. The certification requirement last year demanded that the president show an improvement in human rights and progress in bringing to justice the slayers of former diplomat Orlando Letelier.

The State Department has not attempted certification yet and there are reports it is reassessing its plan to do so. Sen. Edward M. Kennedy (D-Mass.), who has declared that the administration cannot honestly certify Chilean cooperation in the Letelier case, is preparing for a lengthy fight if certification is attempted.

The budget requests $50,000 in military training funds for Chile.

Guatemala, regarded by many congressional critics as the most offensive Latin government, is due for $250,000 in military training money, and the congressional tactic in its case may be to attempt a prohibition of military assistance.

Guatemalan aid was cut off by the Carter administration in 1977.

Secretary of State Alexander M. Haig Jr. has called Guatemala the next target of communist insurgency in Central America.

With the many obstacles in its path, the administration has sidestepped, perhaps only temporarily, the issue of military assistance for factions fighting in Angola. Last year, the State Department gave that issue top priority for several weeks but backed down in the final compromise, which gave it the right to send aid to Latin American countries.

Angola is not mentioned in the fiscal 1983 budget requests, although some congressional sources expect a separate request later.