HEARINGS ON THE Boland-Zablocki bill, which would shut down Ronald Reagan's secret war against the Sandinista government of Nicaragua, provoked a nasty storm in the House Foreign Affairs Committee.

By contrast, the hearings in the Inter- American Subcommittee on the possibility of negotiations in the area were as smooth as a lake on a perfect summer day.

The difference suggests that the Republicans, who have become as sentimental about the counterrevolutionaries in the jungles as if they were boys from their own home districts, fear that the Democrats might actually get up their nerve to stop the CIA-sponsored violence in Nicaragua. Obviously, they see no danger that negotiations might break out.

Sol Linowitz, chairman of the commission which bears his name and which made the recommendation that talks take place among all interested parties, including the Soviet Union and Cuba, was the principal witness for the peaceful approach. He was "disappointed" that no opposing Republicans bothered to turn up, and that he encountered not a single hostile question.

Some House Democrats, notably Rep. Wyche Fowler of Georgia, and deputy Democratic whip Bill Alexander, are pushing the Linowitz line. But, Linowitz notes, there has been a great silence from the Senate, and none of the numerous Democratic presidential candidates has found the subject of note. Senate Republican Leader Howard Baker is the only national politician to urge discussions between the United States and the Soviet Union.

The most passionate partisan of the secret war is possibly Rep. Jerry Solomon of New York, who describes himself as "quite conservative." A Marine veteran of Korea, a blustery anti-communist, he interrupted his Democratic colleague from New York, Stephen Solarz, to say that he was "not going to stand by while this committee is about to sell the U.S. down the drain by aiding and abetting the spread of communism."

With that, he stalked out of the room. Several Republicans hurried after him to soothe him and coax him back to his seat.

The following day, when the commitee was about to vote to support the Boland-Zablocki amendment, which makes overt what the counterrevolutionaries are doing somewhat covertly -- that is, trying "to interdict the flow of arms to Salvadorean rebels" -- Rep. Lawrence Smith (D-Fla.) asked to speak.

His voice rising, Smith declared that the "demagoguery" of the debate was getting to him.

"I will not accept the mantle of blame," he shouted. "I resent very much the implication from the administration that anyone who disagrees is not a true American. I will not tolerate it."

Afterward, Solomon denied he was impugning the patriotism of his colleagues. "It's a question of judgment," he said.

Smith said he didn't have Solomon in mind when he spoke his piece. "I tend to disregard most of what he says."

What riles him is the drumfire from the administration about the intentions of its opponents, especially U.N. Ambassador Jeanne Kirkpatrick's remark that "some members of Congress would prefer to see a Marxist takeover of the region."

When pressed at a meeting of 75 House members for the source of her suspicion, Kirkpatrick took refuge in a claim of having been "quoted out of context," and a vague reference to "friends in Congress" who had told her about the communist sympathizers in their midst.

"We asked her which congressmen had been her informants, but she wouldn't identify anyone," said Smith.

All this turmoil prompted Alexander to take the floor to warn that "echoes of the McCarthy era are being heard in the halls of Congress. I would suggest that as we debate U.S. policy, we avoid a return to the dark days of red-baiting."

Solomon is unrepentant. "I don't think there is a witch hunt," he said.

Efforts at "compromise" and "bipartisanship" led by calm Lee Hamilton (D-Ind.) have failed. The recent history of compromise and bipartisanship led in the case of the MX to what one of the Democratic bargainers, Rep. Les Aspin of Wisconsin, called "the minimum."

In covert action in Nicaragua, there is no middle ground. It's either stop or go. But Democrats are nervous. Rep. Dante Fascell (D-Fla.) voted against the shutdown.

"The important thing is not that the president is breaking the law," he said. "The important thing is what the other side is getting away with."

The time for recriminations is upon us in Central America. It has come early, because the one lesson learned from the late senator from Wisconsin is that calling the Democrats "soft on communism" not only sends them up the wall, but can play well in the country, too.