The stakes are high: Iran’s regional rivals have staked their hopes for a reversal of fortune on Trump’s willingness to embrace traditional Sunni allies and take military action against Assad, while Iran and its allies believe themselves on the verge of a total victory in Syria.

And while the strike may have been undertaken more in self-defense than as part of any shift in policy, the Trump administration has been actively seeking ways to repel Iran, canvassing the Pentagon as well as U.S. allies in the region for suggestions about where and how to draw lines against what it views as Iranian expansionism. American experts with experience in the region, and in the U.S. government, say they have been consulted about possible pressure points. In my conversations with senior Arab officials, they have shared their own proposals in detail. The strikes against Tanf may well suggest that America is moving out of the planning stage and into a period of military action intended to abate Iranian momentum.

For those who believe that Iran has gone too far—in Iraq, in Syria, in Lebanon, and in Yemen—any forceful pushback is welcome. But the United States needs to be careful. Boxing in Iran and its proxies could advance U.S. interests and restore the regional balance of power, but only if military force is deployed as part of a careful strategy that maintains America’s distance from Iran’s problematic allies.

So far, there are no indications that the Trump administration is doing any of the necessary groundwork to insure against blowback or out-of-control spiraling as America appears to turn from accommodation and containment to military force. The Obama administration pursued a cautious, conciliatory approach to Iran, avoiding any direct clashes in the belief that all other concerns were secondary to the nuclear negotiations, and that a relatively minor clash over Syria or Yemen could upend years of talks to freeze Iran’s nuclear program. In practice, the regime and its clients learned that they could behave as recklessly or maximally as they wanted in pursuit of their interests in the Middle East without fear of a robust U.S. response, even in places like Iraq. Obama administration officials say they believe this approach allowed them to win international support for the nuclear deal and to portray Iran, rather than the United States, as the problem party in the negotiations.

It’s just as likely that nuclear negotiations would have produced the same outcome even if the United States had pushed back against Iranian actions in Iraq, Syria, and Yemen, prior to the conclusion of the deal. But once the nuclear deal was concluded, Obama made a poor choice, joining forces with Saudi Arabia and the United Arab Emirates in an ill-planned campaign in Yemen that has hobbled the state, wantonly targeted civilians, opened new space for al-Qaeda, and strengthened, rather than reduced, Iranian influence over Yemen’s Houthi rebels. Meanwhile, he left Iran and its proxies a free hand in Iraq and Syria. The result today is a triumphalist Iran, whose allies and proxies can claim a dominant position in Iraq and Syria, and whose military and political rise was, in many instances, directly abetted by the United States.