Guy Snodgrass is chief executive of Defense Analytics, a strategic advisory firm in the District. He is a retired U.S. Navy commander and most recently served as director of communications and chief speechwriter for former defense secretary Jim Mattis. He is the author of “Holding the Line: Inside Trump’s Pentagon with Secretary Mattis.”

The global threats that the U.S. military faces are the least of its concerns.

Sure, the actions recently attributed to Iran — damaging two tankers in the Gulf of Oman and shooting down a drone — have further inflamed an already tense situation in the Middle East. But Iran shouldn’t keep us up at night. Nor should North Korea’s threats to resume testing ballistic missiles. Or China’s ongoing attempt to militarize the South China Sea, slowly shifting the Indo-Pacific’s balance of power. Even Russian attempts to ignite a hypersonic arms race worry me less than what is going on inside the Pentagon.

The Pentagon is in far greater trouble because of one simple reason: a lack of leadership.

The Pentagon recently surpassed a previously-unthought-of milestone — 6 1 / 2 months without a Senate-confirmed secretary at the helm. Mark Esper, the president’s new nominee for the position, was the second person to serve as acting defense secretary. The Federal Vacancies Reform Act of 1998 ensured that a third acting secretary — Richard V. Spencer, the secretary of the Navy — temporarily took the helm Monday, as Esper cannot serve as acting secretary while under consideration for the permanent appointment.

The Senate rightly fast-tracked Esper’s nomination, holding the hearing before its Armed Services Committee on Tuesday, and his strong performance seemed to assure his confirmation, with a floor vote anticipated on Thursday.

Even still, this long-standing leadership vacuum is compounded by a Pentagon with an acting deputy defense secretary, acting secretary of the Army, acting secretary of the Air Force, acting inspector general, acting assistant defense secretary for international security affairs . . . the list goes on. CNN revealed earlier this month that 19 of the most senior Pentagon positions are either vacant or filled by a temporary acting official. Lower-tier leadership posts are similarly gapped. Friends serving in the Pentagon describe a disordered situation, where no one can speak with confidence regarding the military’s long-term priorities.

This situation is untenable. It took a turn for the worse when Adm. William Moran, the Senate-confirmed chief of naval operations, resigned last week before ever taking office. Adm. John Richardson will remain the Navy’s top officer before reaching mandatory retirement in September. The race is now on to identify, vet and nominate a replacement before time runs out.

Then, on July 10, Gen. John Hyten’s nomination as the next vice chairman of the Joint Chiefs of Staff — the second-most-senior uniformed officer in the United States — was placed at risk by allegations of misconduct. Although military officials deemed the allegations insufficient to bring charges, he could become a politically unpalatable choice for the job. Gen. Paul J. Selva, who holds the job, retires at the end of this month.

Under any normal circumstances, even a week without a defense secretary could present a dangerous leadership vacuum in the Pentagon. That the position was vacant for more than six months — and that this lack of leadership has become systemic — is shocking. This chaotic security situation emboldens U.S. adversaries, alarms allies and erodes the Defense Department’s ability to retain the talented careerists needed for the military’s long-term health.

It also delays the transformative change the military sorely needs.

The 2018 National Defense Strategy acknowledged that the U.S. military is “emerging from a period of strategic atrophy, aware that our military advantage has been eroding.” The strategy cited as reasons an increasingly complex security environment, rapid technological change and the impact to readiness from 18 consecutive years of war, requiring that we prioritize “what is most important to field a lethal, resilient, and rapidly adapting Joint Force.”

But how does one prioritize without a leader? How can the Pentagon “gain full value from every taxpayer dollar” or “deliver performance at the speed of relevance” without Senate-confirmed senior leadership?

One benefit of a vast bureaucracy is inertia — the ability to weather short periods of change, such as administration swap-outs following a presidential election. But inertia can carry you only so far. The reality is that a ship without a captain can remain afloat, but the ship’s effectiveness degrades rapidly without a leader.

The U.S. military — and the United States itself — must have a real defense secretary. If voted through, Esper and the administration must prioritize putting Senate-confirmed leaders in place at the Pentagon. The military needs leaders empowered to speak from a position of strength, with Congress’s vote of confidence behind them.

Only a real — not acting — defense secretary can enact the strategic changes needed to restore the military and steer the Pentagon from away from its rudderless course. While our uniformed military leaders are well-equipped to respond to conflicts overseas, only senior civilian leaders can provide the overarching policy guidance they require.

President Trump declared during his Fourth of July address that “our nation is stronger today than it ever was before.” Unfortunately, his statement does not reflect ground truth at the Pentagon, where actions — or a lack thereof — speak louder than words ever could. The world won’t wait for senior leaders to be nominated and confirmed. Today’s flash points are already here, and more are likely on the way.