ABU DHABI -- Arab leaders love the idea that President Trump is ready to give Iran a punch in the nose. But is this White House truly serious about challenging Iranian power in the Middle East? The evidence is mixed, at best.

I heard passionate enthusiasm for Trump's decision to withdraw from the Iran nuclear deal from prominent Arabs gathered in Abu Dhabi last weekend for a conference sponsored by the Beirut Institute. They know that scuttling the nuclear deal could be dangerous, and that the region is already a powder keg. But many Arab leaders don't seem to care.

To put it bluntly, they like the idea that Trump is willing to stick it to Tehran. Though they expect an Iranian counterpunch, they're not as worried about it as you might expect. Several prominent Arabs predicted that Tehran will eventually bend to pressure, if there's a united front.

Prince Turki al-Faisal, a former Saudi intelligence chief and hardly a shoot-from-the-hip hothead, argued that maybe the Iranians will react like North Korea's Kim Jong Un, "who seems to have accepted Trump's 'bigger button.'" Facing Trump's demand for concessions on the duration of the nuclear agreement, Iranian missile programs and regional meddling, "Iran might change its mind," he told the conference.

Arab leaders should consider the possibility that Trump has it backward: The right strategy would be reversing Iran's power grab in the Middle East while preserving the nuclear deal as an element of regional stability. Trump's instincts, in contrast, seem to be the opposite, as Karim Sadjadpour of the Carnegie Endowment for International Peace told me recently; that is, Trump wants to get out of both the nuclear agreement and the region.

A serious strategy to roll back Iran would begin with Syria. The U.S. would maintain the strong military position it has established east of the Euphrates, and enhance its garrison at Tanf and other points in southern Syria. Trump's public comments suggest, however, that he wants to pull these troops out, the sooner the better. This would all but assure continued Iranian power in Syria.

Iraq is another key pressure point. The victory of militant Iraqi nationalist Moqtada al-Sadr in Saturday's elections should worry Tehran as much as Washington. Sadr has quietly developed good relations with Saudi Arabia, and his movement may offer the best chance of maintaining an Arab Iraq, as opposed to a Persian-dominated one. But again, that's assuming that Washington is serious about backing the Saudis in checking Iran's regional ambitions.

Getting both Iran and Saudi Arabia out of Yemen would help, too. That would require a mix of subtle pressure and diplomacy from a Trump administration that has shown little skill at either so far in the Middle East. But it's a worthy goal for Mike Pompeo, the new secretary of state.

Rolling back an aggressive rival seems impossible, until someone dares to try it. Think back to the Reagan presidency, when policymakers considered the once-unthinkable possibility that America and its allies could dislodge the Soviets from the Third World and, eventually, from Eastern Europe and the Soviet Union itself. After a decade of challenge, Soviet power was gone.

To be sure, past attempts to contain an expansionist, revolutionary Iran haven't had much success. Saddam Hussein's invasion of Iran in 1980 produced an eight-year quagmire. Saudi Arabia's invasion of Yemen in 2015 has also been a bloody slog, and has brought Iranian missile attacks on Saudi territory. The proxy war in Syria has been catastrophic.

The Arabs want the U.S. (or Israel) to do the fighting this time. That's a bad idea for America, for many reasons, but the biggest is that there's no U.S. political support for a war against Iran.

So what's the pathway to containing Iranian meddling? It probably passes through Moscow. Russian interests in the region are complicated. Moscow may be fighting alongside Iran in Syria, but it also has growing economic and diplomatic links with Israel, Saudi Arabia and the United Arab Emirates.

"Iran is a tactical ally. Russia needs a constellation of partners," Russian foreign-policy analyst Andrei Bystritsky told the conference here. And unlike the Iranians, who want to stay in Syria, "The question for us is how to leave," argued Russian former Deputy Foreign Minister Andrei Fedorov.

Trump has embarked on an Iran mission that lacks a clearly defined objective. Here's a suggestion that draws on the lessons of the Reagan years: The right combination is combating regional meddling, plus maintaining arms control. Thinking rollback isn't crazy, but it requires a sustained effort, not a grandstand play.

David Ignatius' column is distributed by the Washington Post Writers Group.