Rebel fighters take a position in the countryside of the northern Idlib province of Syria on Aug. 17. (Omar Haj Kadour/AFP/Getty Images)

THE CIVIL war in Syria may be on the verge of another turn for the worse. Syrian government and allied forces are reportedly massing for a potential assault on the northern province of Idlib, one of the last areas of the country not under government control. Tens of thousands of rebel fighters are based there, including forces linked to al-Qaeda, along with some 3 million civilians, many of whom are refugees from other parts of the country. An offensive by the regime could mean thousands more deaths and drive a new wave of refugees toward neighboring countries, as well as Europe. Meanwhile, efforts by Iran to entrench itself in the country risk triggering a war with Israel.

National security professionals in the Trump administration appear to recognize these dangers. Last week, Secretary of State Mike Pompeo named a seasoned diplomat as special envoy for Syria, charged with reviving a U.N.-sponsored peace process. In a briefing, senior officials told reporters that U.S. forces based in eastern Syria would not be leaving anytime soon and insisted that reconstruction aid for government-controlled areas would be blocked until an acceptable political process was underway. On Wednesday, national security adviser John Bolton publicly warned the regime of Bashar al-Assad not to employ chemical weapons in any new attack and said the United States was determined to “deal with the presence of the Iranians.”

Any U.S. strategy in Syria would face steep obstacles, including the machinations of Russia, which claims to want to restrain the regime and remove the Iranians but, in practice, abets both. Yet the unique problem with this U.S. policy is that it is at odds with the stated positions of President Trump. Mr. Trump has repeatedly and bluntly declared that he wishes to withdraw U.S. forces from Syria as soon as possible; he has insisted on canceling U.S. stabilization aid to the area where those troops are deployed; and after meeting privately with Russian President Vladi­mir Putin in Helsinki last month, he appeared to endorse Russia’s plan for reconstruction, unlinked to any peace process.

In essence, Mr. Trump’s aides are attempting to coax him into sustaining the U.S. presence in Syria while pressuring rather than pandering to Russia. It’s sensible policy — or, at least, the best of an array of bad options — but the president’s resistance means its chances of working are slim.

To placate Mr. Trump, officials raised $300 million from Saudi Arabia and other allies for stabilizing the region around the eastern city of Raqqa, the former Islamic State capital now held by U.S.-backed Kurdish and Arab forces. That’s more than the $230 million Mr. Trump insisted on canceling. But a tweet the president issued afterward again revealed his underlying view — he dubbed U.S. aid “ridiculous,” something that is not likely to inspire confidence in other American commitments. As it is, the Kurds, all too aware of the precariousness of the U.S. presence, have begun negotiating with the Assad regime about a settlement outside the U.N. process. Israel already struck its own deal with Russia to keep Iranian forces away from its border.

What all sides in Syria perceive is not only a lack of U.S. resolve. They also see an administration that hasn’t been able even to formulate a clear strategy to defend American interests — thanks to the poor judgment of the president.