N.Y. Blast Could Throw U.S. Into Diplomatic Dilemma : Strategy: White House is planning its response if a foreign group or renegade nation is involved. But those steps create new policy problems.

As investigators track the conspiracy that led to the World Trade Center bombing, Clinton Administration foreign policy strategists are drafting contingency plans that could be used if the trail leads to a terrorist group or a renegade nation.

The list includes possibilities ranging from military retaliation, as the United States used against Libya in 1986, to an assortment of diplomatic measures or legal moves, such as a toughening of immigration laws.

Officials acknowledge that few of the options are attractive because most could produce unintended consequences for the Middle East peace process or impinge on the civil liberties of people with no involvement in the terrorist attack.

Nevertheless, they say there is growing public and congressional pressure to take action against those responsible for the trade center bombing.

“If there is an international aspect to this, it will be followed,” Thomas McNamara, the State Department’s coordinator of counterterrorism efforts, said Friday.

But McNamara emphasized action against the individual perpetrators over possible retaliation against organizations or governments.

“The message that we wish to send out to terrorists is that you can’t hide,” he said. “And no matter how long it takes, we’re coming after you and we’re going to get you.”

But with investigators having confirmed that thousands of dollars were transferred from overseas into bank accounts of two chief suspects in the attack, evidence seems to point increasingly to some organized foreign participation in the bombing plot.

“I think it is clear now (that) it’s an organized attack,” said L. Paul Bremer, a former State Department counterterrorism official. “Whether it will lead back to a state or a known terrorist group I think is still an open question.”

If it does turn out that an organization or a government was involved, the Administration would face sensitive foreign policy questions. Perhaps the most complicated problem would be to craft an effective blow against a radical foreign group.

Regional experts say there are substantial limits on the actions the United States could take against an organization that has its headquarters abroad. For instance, military action against a group located in a country like Iran, Libya or Syria would be almost as awkward as action against the host government itself.

“People related with the groups ought to be kicked out of the United States,” Bremer said. “I have long been in favor of a rapid deportation process. But the most effective measures against these groups is good intelligence to prevent attacks and good police work to put them in jail. You just have to keep at it.”

Secretary of State Warren Christopher agreed that it may be time to stiffen visa and immigration procedures to keep potential terrorists out of the United States.

In testimony on Capitol Hill this week, Christopher said the trade center bombing “is a reminder to us that we ought to try to avoid having in our country people with a history of that kind of relationship with extreme causes and . . . terrorist acts.”

But even anti-terrorism hard-liners worry that the response to the trade center bombing may infringe on civil liberties and result in a backlash against Muslims who had nothing to do with the attack.

“The problem is not with Islam,” McNamara said. “It is with those extremists, few in number but very dangerous, who use violence and terror to advance their objectives.”

But Robert Hunter, a former National Security Council specialist, warned that the distinction may be difficult to sustain.

“You have to ask how much damage you do to yourself by overreacting,” said Hunter, now a scholar at the Center for Strategic and International Studies in Washington. “Ultimately there is nothing you can do about people who are crazy enough to plant bombs. Already there has been speculation that sensitizes people about Islam. It may just increase fears and make it harder to differentiate between the various strains of Islam.”

Regional experts say the pressure to retaliate would be much greater if a foreign government is ultimately implicated.

“If it’s a government, we will take very strong action,” said William B. Quandt, a former National Security Council expert on the Middle East who is now a scholar at the Brookings Institution in Washington. “I think there would be very strong pressure to take action if there were clear-cut evidence that a government was involved. But in the real world, it is extremely unlikely that there will be clear-cut evidence.”

It is not hard to devise a list of governments that might have a grudge against the United States. Iraq, Libya, Iran, Syria and others qualify. But Syria seems to have decided that, following the demise of the Soviet Union, it must improve its relations with Washington. So it seems unlikely that Damascus would risk involvement in something like the trade center attack.

Iraq and Libya clearly have the motive, but neither has indicated that it has the resources to challenge the United States on its own ground. That leaves Iran as virtually the only country that might have both the means and the motive, and most experts say they doubt that the Tehran government would take that sort of risk for a relatively small payoff.