WASHINGTON — For months, American Jewish leaders have worried that a U.S. attack on Iraq could prompt new and possibly deadlier attacks against Israel by Saddam Hussein, the man who lobbed 39 Scud missiles at the Jewish state during the 1991 Gulf War.

But there is growing concern about another kind of attack as the massive U.S. deployment to the region continues. Because of a confluence of factors, an unpopular Gulf War could produce new flare-ups of anti-Semitic violence aimed at the vulnerable Jews of Europe.

That concern has been seconded by the Bush administration.

In recent weeks State Department officials have quietly urged their European counterparts to take pre-emptive action to prevent new anti-Semitic attacks in the wake of a U.S.-led military action against Iraq.

European officials have listened — but that's about all. Some have even used the threat of anti-Semitism as one more piece of ammunition in their effort to block the expected U.S. attack.

The Bush administration is getting high marks even from Democrats for urging pre-emptive action by the balky Europeans.

"I have been very impressed with their response," said Rep. Ben Cardin (D-Md.), a senior member of the Jewish delegation in the House and a member of the Helsinki Commission — a congressional group that monitors human rights in Europe. "There is a real sense of urgency, and I think it's justified."

But Washington's impact may be limited, largely because the expected reaction is closely linked to the surging anti-Americanism that European leaders themselves have tacitly encouraged.

The potential problem has multiple causes.

Increasingly, the European left is allied with Muslim and pro-Palestinian forces that have crossed the line from forceful criticism of Israel's policies to anti-Israel and anti-Semitic incitement.

That has produced new spasms of anti-Semitism across Europe since the breakdown of Israeli-Palestinian negotiations in 2000. The prospect of a U.S. war against Iraq has provided another boost to these forces and created new ties with more moderate groups opposed to U.S. policy.

A major contributing factor is surging Muslim populations, especially in France, where Islamic immigrants vastly outnumber Jews.

Last week American Jewish Committee leaders met with French President Jacques Chirac, who called anti-Semitism a "cancer" and warned that an Iraq war could result in new attacks against Jews. But characteristically, Chirac seemed more interested in using that threat as another argument in his effort to block U.S. action against Iraq.

That attitude — hostility to U.S. policy and indifference in the face of rising domestic anti-Semitism — is all the more reason why a U.S. Gulf strike may produce new violence and vandalism against Jewish targets.

The problem is evident in Germany, as well, where anti-Iraq war and anti-Israel sentiment is running strong, with government encouragement.

All across Europe, anti-war activists and the media suggest Israeli "aggression" and U.S. "bullying" are two sides of the same coin.

In recent weeks the Bush administration has quietly urged European nations to take steps now to defuse the potential backlash.

In meetings with leaders of the World Jewish Congress, top administration officials revealed that they have quietly urged European leaders to develop pre-emptive plans for limiting the backlash, said Avi Beker, secretary general of the group.

"They made it clear they take this very seriously," he said, "that this is something they have to do as part of their war planning."

The congressional Helsinki Commission has acknowledged the potential and urged the European nations to take an inventory of the programs available for fighting anti-Semitism and other forms of bigotry, said Cardin.

"In France, in particular, the rise in anti-Semitism in the past was directly related to Middle East events," he said. "We expect that when there is even more tension in the region, there will be more open anti-Semitic activity; individuals will try to justify their anti-Semitism as based on world events. So we do believe we will see a rise in open anti-Semitism."

The administration is right to raise the alarms with European diplomats, but its influence is limited — in part because it will also be a backlash against an administration that the rest of the world sees as a unilateral bully.

European leaders are not in the mood to listen to a president they dislike, and they aren't interested in confronting domestic forces that will seize on the Iraq war to foster and justify new anti-Semitism at home.

Jewish groups like the World Jewish Congress, the American Jewish Committee, the Anti-Defamation League and the Simon Wiesenthal Center are redoubling their efforts to pressure European leaders to work in advance to prevent a violent backlash.

Many Israeli leaders are hoping the U.S. effort in Iraq will succeed and that administration predictions that it will trigger a regional shift to more moderate regimes prove correct.

But Jews in Europe, like their American counterparts, are divided about prospects for war with Iraq. Blaming Jews for what could prove to be a highly unpopular war is a far-fetched fantasy that, unfortunately, too many people seem willing to believe.