Although polls now show a slight majority of Americans favor military action against Iran, voices in the nation's civilian and military leadership are warning of the possible consequences.
More than half of the Americans asked by the Washington Post and the Harris-ABC News survey recently said they supported unspecified military action against Iran if the American hostages were not freed. President Carter has indicated military options may be used if trade and other economic sanctions fail, and if US allies do not join these sanctions.
Fifty-five percent of 1,873 people asked by the Post said "yes" to the proposition that the United States should set a deadline for return of the hostages and take military action if it is not met. Thirty percent, however, favored no military action, no matter how long the hostages are held.
An earlier Harris-ABC News poll, conducted just before the President's nonmilitary sanctions were announced, disclosed rising criticism of the President's handling of the crisis. A 51-to-39 percent majority agreed with the view that "the US should take military action against Iran, if Iran puts some of the hostages on trial as spies, even if that might endanger the lives of the hostages."
Strongest among the voices of caution has been Sen. Robert C. Byrd (D) of West Virginia, the Senate majority leader. He expressed sympathy with Mr. and Mrs. Kenneth Timm, parents of a US Marine hostage, who flew to Tehran to try to see their son.
Senator Byrd warned that "it's extremely difficult to envision any direct military action to free those hostages unharmed." Speculation about it was harmful, he said. Military action might only destroy Iranian moderates who want the hostages freed and invite Soviet action. "Let's stop, look, and listen," Senator Byrd urged.
* Alfred E. Kahn, the Carter administration's anti-inflation chief, warned that a naval blockade -- one of the main military options the Pentagon is studying -- might bring gasoline rationing "quite soon" to the US.
Mr. Kahn said this was because Japan at present imports 13 percent of its oil from Iran, meaning it could not tolerate a blockade unless the US could curb its own consumption. Cutoff of Iranian oil to Japan, he told Texas newsmen in Fort Worth, would put Japan in competition with the US and other Western industrial states for foreign oil.
Military choices for the US, according to uninformed service commanders and civilian analysts with whom this reporter has spoken, include:
* A full blockade of Iran or a naval and air "quarantine" to inspect shipping to and from Iran, before it enters the Persian Gulf or (if this is determined) tankers carrying Iranian oil away from the Gulf.
* Mining of Iran's Persian Gulf ports by air drop from US Air Force bombers, or Navy patrol planes, or Navy planes based on the two US aircraft carriers near Iran in the Arabian Sea. Some Navy professionals favor this.
* A surprise rescue of the hostages using open or, more likely, covert infiltration by US special forces troops. The Army, Marine Corps, Air Force, and Navy all have such forces.
Gen. Dan Shomron, the Israeli general who commanded the rescue of hijacked Israeli hostages from Uganda, urged April 20 in the Israeli newspaper Davar that this is feasible and possible. The proliferation of armed students, guerillas, and other gunmen in and around the embassy compound would make it easier, General Shomron argued.
Miles Copeland, author of books on covert action in the Middle East and a former Central Intelligence Agency officer, urged in a US television panel and an interview in the Washington Star April 20 that covert forces, using if possible "Iranian helicopters" flown by Iranian pilots trained in the US (some of whom stayed behind when about 200 Iranian military trainees were expelled from the US early this month) should paralyze the embassy compound with sleep-inducing gas, then rescue the hostages.
"We have the capability," Mr. Copeland said."It's at Ft. Bragg."
At Ft. Bragg, N.C., two US Special Forces groups, the Fifth and the Seventh, and the US Army Institute for Military Assistance, which includes a school for the "green berets" of the special forces, do train paratroop-qualified soldiers and officers for guerrilla missions.
Another Ft. Bragg organization, the John F. Kennedy Center for Military Assistance, trains men and exchanges information with visiting allied, Israeli, and other "friendly" specialists, on what a JFK Center officer describes as "unconventional warfare, psychological warfare, and civil affairs."
Though the CIA has largely lost its well-publicized covert-action capabilities, the Army at Ft. Bragg (another special forces group is stationed at Ft. Devens, Mass.) has cultivated its own much less-publicized capabilities since World War ii.
Mining of Iran's main Persian Gulf ports of Bandar Abbas, Bushehr, and the oil terminal installations at Kharg Island, Bandar Shahpour, and Bendar Mahshahr , some seapower buffs say the believe, could be done "selectively."