Events in the Middle East can take quick, unforeseen turns. Washington is having to keep this volatility in mind as it tries to rally support for its policies in the region. And high among its concerns is just what the closest US ally there, Israel, will do when provoked.
Consider the Israeli siege of Yasser Arafat's battered headquarters in the West Bank city of Ramallah. It began after last week's renewal of Palestinian suicide attacks.
Those attacks were launched, as usual, by extremist factions over which Mr. Arafat has little, if any, control. But Israeli leader Ariel Sharon seized the moment to refocus his military might on Arafat's compound. Some speculate the goal is to make life so miserable for the Palestinian president that he finally agrees to exile.
Arafat, however, seems to revel in the situation, vowing he'll never wave a white flag, turn over even the names of those trapped with him (some of whom are wanted by Israel), or leave Palestinian soil.
Arafat's cause received some help from a United Nations Security Council resolution (with the US abstaining) calling for Israel to lift the siege. Israel, however, is likely to ignore the UN call and is in fact broadening its military operations, thrusting deep into Gaza to demolish weapons workshops and the houses of suspected terrorists.
Washington has to view all this with alarm. The Bush administration has rightly criticized the siege of Arafat's compound as damaging to efforts to reform Palestinian government and sideline Arafat peacefully. Instead, popular opinion is rallying around the embattled leader.
The US also can't help worrying that any excessive use of force by Israel could derail efforts to muster support among Arab leaders for military action against Iraq. Certainly Israeli defiance of the UN resolution will generate new charges of a double standard: Why can Israel violate such resolutions while Iraq can't?
US worries had to be deepened by the Sharon government's declaration that if there were another war in the Gulf, and Iraqi missiles took flight toward Tel Aviv, Israel would not restrain itself as it did in 1991.
Sharon did ease the Ramallah siege as US criticism mounted. Washington's voice is heard. But there's always the possibility that, given Israel's own very strong ideas of how to deal with unfriendly neighbors, that voice may not be fully heeded.
The fact is, however, that Bush plans in the Middle East could hinge on a cooperative Israel.