SAN SALVADOR, NOV. 4 -- "If these guys want to play hardball, we're prepared to play hardball," the Rev. Charles Beirne, member of the Society of Jesus, was saying the other day. "Popping us off would be a very costly action."

Beirne has given considerable thought lately to death -- or getting "popped off," as he puts it in his decidedly non-pastoral parlance. He is one of a team of priests who arrived at the Jesuit-run Central American University here to replace the six priests whom Salvadoran troops killed last Nov. 16 at the campus rectory, along with a housekeeper and her daughter.

Beirne, a former associate dean of business administration at Georgetown University, is the new vice rector for academics at the university here, known by its Spanish initials as UCA. As an American, he trusts that his political contacts in Washington will constitute what he calls an "insurance policy" to help keep him alive.

He notes that on a trip to Washington earlier this year, he met Salvadoran President Alfredo Cristiani and Col. Rene Emilio Ponce, El Salvador's defense minister, in the Capitol Hill office of Rep. Joe Moakley (D-Mass.). Moakley is head of a congressional task force investigating the Jesuits' deaths and was a driving force in Congress's decision last month to halve U.S. military aid to this country.

"When they saw me coming out of Joe Moakley's office, I'm sure they knew I wasn't there to discuss the weather in Massachusetts," he said.

A few days ago, Beirne showed a visitor around UCA's leafy campus, where students and faculty are marking the 25th anniversary of the university's founding as well as the first anniversary of the killings.

At the red-brick rectory where the six priests were shot at close range with assault rifles, the blood stains have been washed away, the bullet holes patched up and the scorch marks repainted. But the memories, Beirne said, live on.

Downstairs -- where Salvadoran soldiers apparently unleashed a barrage of fire from heavy machine guns and flamethrowers in an attempt to suggest a firefight -- a display commemorates the predawn massacre.

Three or four thick theological tracts lie open to pages rent and shredded by the paths of bullets. Nearby is a portrait of archbishop Oscar Arnulfo Romero, who was murdered in 1980. His likeness is dappled and disfigured by the intense heat of the flamethrowers, and melted glass hangs from the picture frame like giant icicles.

"They really did a job on this place," said Beirne.

Beirne, who had visited El Salvador a half dozen times since 1980, was a friend of all six of the priests slain last year. A few hours before the attack, he chatted on the phone from the United States with the Rev. Ignacio Martin-Baro, UCA's vice rector and a respected pollster and psychologist.

The city was in the grip of an all-out offensive by leftist guerrillas, and Martin-Baro noted that the UCA campus was surrounded by soldiers, Beirne said. A few hours later, Martin-Baro was dead.

After the killings, Beirne spoke with the Rev. Jose Maria Tojeira, the head of the Jesuit order in Central America, about taking a job at UCA. At the time, Beirne, who has advanced degrees in history, education, philosophy and theology, was academic vice president of Santa Clara University, a Jesuit institution in California.

He also was in the running for the presidencies of two Jesuit institutions in the United States. When one of them selected another candidate, Beirne decided to go to El Salvador. Today, he has Martin-Baro's old office.

The dead Jesuits had pushed for a negotiated settlement of the civil war that would address the country's social inequities and rein in the excesses of its army. That position had earned them the enmity of the armed forces, who considered the Jesuits the intellectual godfathers of the country's leftist guerrillas, providing the rebels with an unwarranted veneer of moral legitimacy.

Despite the army's distrust of the Jesuits, the Rev. Ignacio Ellacuria, UCA's rector, had developed a close relationship with President Cristiani. In a polarized society, he was one of the few prominent figures who commanded respect both in the presidential palace and the guerrilla directorate. Until Nov. 16, Ellacuria served as an informal intermediary between the two.

Today, Beirne speaks with reverence of Ellacuria, Martin-Baro and the others slain that night. "These men were giants," he said. "There's no way anyone could replace that right away."

The new team, which beside Beirne includes another American, a Canadian, two Spaniards, a Mexican and a Salvadoran, is taking up the mantle of their slain colleagues at a delicate time, both for UCA and for the nation.

With the Salvadoran civil war stalemated in its 11th year, the guerrillas are threatening a new military offensive and the armed forces, stung by a sharp cut in aid from the United States, are on the political defensive.

But if the political atmosphere is tense, Beirne, whose acid tongue belies an avuncular manner, seems unwilling to tone down his fighting rhetoric. His most barbed criticisms are of U.S. policy, which has pumped $1 billion in military aid into El Salvador in the last decade but failed to give the Salvadoran military a decisive advantage in the war or rid it of human rights abuses.

"Their project stinks to high heaven," he said. "They have very little to show for their investment."

Beirne has met just once with U.S. Ambassador William Walker, shortly after arriving here in August. Since then, he says, he and the Rev. Dean Brackley, a theology professor who is the other new American priest at UCA, have not been invited to any embassy functions.

"Our attitude is one of general disgust with U.S. policy," Beirne said. "They talk about improved human rights, but the assassinations of the Jesuits belie that."