President Clinton signed an executive order that derails the Houston-based Conoco's lucrative deal to develop two Persian Gulf oil fields for Iran through a foreign subsidiary. The move, which TIME Defense correspondent Mark Thompson says came after Clinton's weekend efforts to "choreograph" a graceful withdrawal by the firm, bars any U.S. citizens or companies from signing oil development contracts with the Iranian government. Clinton acted to reinforce a U.S. crackdown on Iran's support of international terrorism, on its efforts to undermine Middle East peace and Tehran's possible development of nuclear weapons. "The problem was not the deal, it's what the Iranians might do with profits from the deal," says Thompson. "U.S. oil companies have been buying Iranian oil for a long time with their offshore subsidiaries, but the Conoco deal would have generated hard currency for the Iranians to spend on mischief."