Washington — The grim-faced, implacable Ayatollah Khomeini remains one of the United States' bitterest foes. His hand, US government officials charge, urged on the suicide bomber who blew up the US Marine barracks in Beirut. Khomeini's Iran, last month, even issued a postage stamp commemorating the '79 takeover of the US Embassy in Tehran.
But Iran's aversion to things American apparently does not include the dollar. Trade between the two nations, almost nonexistent in recent years, was up sharply in 1983: US imports from Iran now almost equal those from Israel.
Ironically, at the same time US economic ties with cash-strapped Iraq have weakened. Many US policymakers want America to act friendlier toward Iraq (now at war with Iran) as a kind of diplomatic revenge against Khomeini's regime.
In the years when the Shah sat on his Peacock Throne, Iran was one of the US's biggest business partners. In 1978, US firms exported $3.7 billion worth of goods to Iran - more than they sold to any nation outside of Western Europe and Japan.
The Islamic revolution that replaced the Shah with Khomeini ended all that. The flow of fat orders for US arms suddenly dried up; in turn, Iran shipped hardly a tin of caviar or single carpet, much less a tanker of oil, to the US. President Carter slapped restrictions on financial dealings with Iran. By 1981, US-Iranian trade was so small the Commerce Department didn't even bother to measure it.
But over the last several years Iran has quietly been setting straight its financial dealings with the United States. Twenty-five US banks, and about 100 US corporations, have now been paid back for losses stemming from the '79 Iranian revolution. (There are still a lot of people clamoring for their money: 400 large claims and thousands of small ones remain unsettled.)
And cargo ships are once more sailing from Iran to the US, carrying goods. US direct exports to Iran - mostly oil drilling and refining machinery, and food - are still small, totaling $160 million through October, according to Commerce Department statistics. But direct imports from Iran - 90 percent of them petroleum products - have almost doubled from the year before, ringing in at $ 932 million for the first 10 months of '83.
By way of comparison, US imports from Israel were $1.1 billion for the same period.
One thing shown by these figures, say experts on the Mideast, is that commerce has a way of confounding politics. But they add that by no means are the US and Iran moving toward a warm economic relationship.
Trade between the two countries ''was just so low before'' that anything looks like an upswing, says Vahan Zanoyan, director of Wharton Econometric Forecasting's Mideastern service.
The oil we import from Iran, estimates Mr. Zanoyan, is only about 1.5 percent of total US consumption. Other experts say the petroleum is mostly special products - very lightweight oil, for instance.
''Iran's important trade connections are with Europe now,'' adds Barry Rubin, a fellow at Georgetown University's Center for Strategic and International Studies. ''I really don't think they are that eager to increase trade with us.''
On the other hand, a country that does want to tighten its economic ties with America, Iraq, is watching its US trade disappear before its eyes.
Some projects are still progressing. DeLeuw & Cather, a US engineering firm, recently signed a contract to design a section of Baghdad's new $2 billion subway, for instance.
But Iraq's purchases from the US have been slashed in half since 1981, to about $450 million through October of '83. Iraqi sales to the US, mostly oil, have dried up even more, totaling only $59 million for the same period. (That's up a bit from 1982, however.)
The war Iraq started against Iran, notes a Commerce Department expert on the Gulf, is the cause of its plummeting export earnings. Syria, an ally of Iran, is refusing to pump Iraqi oil through its pipelines. Since Iraq has limited shipping facilities of its own, this move shuts it out of foreign markets.
At the same time, the stalemated war is draining Baghdad dry. Iraq is now more than $7 billion in debt to its main patron, France.
Thus the opportunity for the US: It could increase its influence in the Gulf, and gain some leverage against Iran, by increasing economic cooperation with the Iraqi regime of Saddam Hussein, some Mideast experts say.
''Iraq is interested in credits. They want money from everybody they can get it from,'' says Mr. Rubin.
Though Iraq severed diplomatic relations with the US in 1967, it has always shown a healthy interest in US goods, instead of the rather shoddy merchandise offered by East Bloc, Rubin says.
Through the late '70s, until it attacked Iran, Iraq increased imports from the US an average of 30 percent a year.