With tensions building in the Persian Gulf, more troops mobilized to the southern border, and Congress marking up the largest military budget in U.S. history, President Donald Trump now finds himself without a secretary of defense—someone who can run the show in all these theaters—for at least another several more months.

Patrick Shanahan, his acting secretary of defense for the past half-year, was expected to face Senate confirmation hearings in July. But on Tuesday morning, he stepped down, citing a sordid set of “family reasons.”

A decade ago, Shanahan revealed, his wife at the time punched him in the face, and, on a separate occasion, his son, citing self-defense, beat her unconscious. The tales of abuse emerged during the FBI’s background investigation, and Shanahan said he didn’t want to dredge it up, fearing that it would ruin his now-grown son’s life.

The withdrawal took place suddenly. He had been scheduled to meet at 11 a.m. on Tuesday with the Defense Policy Board, an outside group of consultants. The meeting was canceled at the last minute, one of the board’s members told me.

Shanahan’s nomination had never been a sure thing. Early on in his tenure as acting secretary, which he assumed after James Mattis resigned in January, he was accused of making derogatory remarks about Lockheed for its mismanagement of the F-35 fighter jet. The remarks were on the mark, but since Shanahan had been a senior executive at Boeing, one of Lockheed’s main competitors, concerns arose about possible conflicts of interest. (An ethics panel cleared him of the charge in April.)

There is no one around Trump right now who has the inclination, the power, or the ability to steer him down a more diplomatic path.

Around the same time, Jim Inhofe, chairman of the Senate Armed Services Committee, said he probably wouldn’t vote to confirm Shanahan to the post, citing his lack of “humility”—a strange accusation, as it could be applied to the vast majority of defense secretaries since the job was created 72 years ago.

Finally, Trump himself didn’t seem enthusiastic about his choice. NBC News reported earlier this month that, during his recent trip to Europe, Trump asked several people what they thought of Shanahan and whether they had any alternative recommendations—often a prelude to subject’s departure. As recently as June 14, in an interview with Fox News, he replied tepidly when asked about Shanahan’s prospects, evading the question the first two times it was posed, then finally saying, “I haven’t put in the final recommendation.”

Shanahan was moved up to the Pentagon’s top slot, though temporarily, after serving as deputy secretary of defense, which is mainly a managerial position. In public appearances, he seemed both tepid in demeanor—one can imagine Trump describing him as “low energy”—and obsequious in his views. The latter was, in some ways, the natural product of his status—in a constant state of auditioning for the job—and knowing, from watching the downfall of the more forceful and independent Mattis, that Trump doesn’t like dissenters.

When Trump was asking about possible replacements for Shanahan, some suggested Mark Esper, a former Raytheon executive who is currently secretary of the Army, a job that usually has no policymaking aspect whatever. And indeed, Trump has named Esper to be the new acting secretary—for how long, nobody can say.

This is hardly the time for someone of little experience or clout to take charge as the military’s civilian leader (second only to the president). Civilian authority in the Pentagon has significantly eroded during Trump’s presidency, sparking an exodus of midlevel officials. Senior military officers have also lost influence, especially since December, when Trump announced—a year ahead of time—the replacement for the current chairman of the Joint Chiefs of Staff, Gen. Joseph Dunford. The chiefs, including Dunford, have opposed several of Trump’s actions—his withdrawal from the Iran nuclear deal, his withdrawal from the Intermediate-Range Nuclear Forces Treaty with Russia, and his recent saber-rattling moves with Iran.

The vacuum in defense circles has been filled by national security adviser John Bolton, who has long pushed for regime change in Iran (and has done everything he can to block Trump’s dubious détente with North Korea), and Secretary of State Mike Pompeo, who basically says and does whatever he thinks Trump wants him to—an attitude that has aligned him with Bolton, especially on Iran.

In recent weeks, Trump has expressed alarm at the momentum toward war with the Islamic Republic, putting out the word that he meant for his “maximum pressure” policy to coerce Iran to the bargaining tables, to negotiate a “better” nuclear deal—not to spark a war. He has said he wants Iran’s leaders to call him and even gave Swiss officials, who have served as intermediaries in past periods of U.S.-Iranian tensions, a phone number where he can be reached.

There is no one around Trump right now who has the inclination, the power, or the ability to steer him down a more diplomatic path. And that’s his fault. He has said repeatedly, since before he took office, that he only hires the “best” people. As he has demonstrated over and over, he has never known—and still doesn’t know—what that means.