Trump’s Next Task: Learning the Limits of Military Power


During its first 100 days, the Trump administration has relied heavily on the U.S. military to address its first set of national security problems. This approach has clearly put adversaries on notice that the new president is willing to employ military power assertively around the world in defense of U.S. interests. Yet it is also very dangerous, because military force is being used absent a more comprehensive approach that integrates all elements of national power. Continuing to rely so heavily on military force risks escalating crises into unexpected, unpredictable, and ultimately more deadly conflicts.

Since Inauguration Day, the U.S. military has launched a cruise missile strike against Syria; intensified air strikes against the self-proclaimed Islamic State in Iraq; used the largest U.S. conventional bomb for the first time, against an Islamic State target in Afghanistan; launched a major raid and increased air strikes against al Qaeda in Yemen; deployed additional troops to Somalia; dispatched F-35 fighters to Estonia; and engaged in confusing saber-rattling with North Korea. Trump directly approved some of these missions, but he has also delegated substantial authority to the Pentagon and military field commanders to conduct operations around the world without prior White House approval.

Why has the Trump administration used the military so frequently? There seem to be at least four reasons. Left unchanged, they suggest that the Trump administration will continue to turn to the military as the first (and possibly only) choice rather than as a last resort — a penchant that could incur dangerous long-term consequences.

First, Trump is, by all indications, enamored with military power. This apparent fascination has taken many forms. It threatens to set the United States on a dramatically different and potentially far more dangerous trajectory in its foreign policy and national security endeavors than any strategy in our history. Candidate Trump pledged to build up and show off the U.S. military, and emphasized using unrestrained force against America’s adversaries. He argued for using torture against suspected terrorists (a position he later reversed), and pledged to “bomb the shit” out of the self-proclaimed Islamic State. His enthusiasm for using military force has not dimmed in office, since he characterized the missile strikes against Syria as “incredible. It’s brilliant. It’s genius.” Trump’s excitement in the trappings and use of military power is almost palpable, and comes across in ways that suggest he may fail to grasp the lethal and unpredictable second- and third-order consequences.

Second, the Trump administration is reducing its non-military options by systematically gutting the civilian elements of U.S. national power, especially diplomacy and development. Its recent budget proposal would slash the budgets of the State Department and the U.S. Agency for International Development (USAID) by a whopping 29 percent — a cut so deep that Senator Lindsey Graham, one of the most hawkish Republicans in Congress, pronounced it “dead on arrival” because it “shows a lack of understanding about what it takes to win the war.” Last week, Foreign Policy reported that the administration is considering abolishing USAID altogether and transferring its responsibilities to the State Department. Moreover, the forceful advocacy for diplomatic options so essential to a robust and balanced interagency discussion of looming policy choices is largely missing because the vast majority of senior positions at the State Department remain vacant. All of this is made worse by a secretary of state who has chosen to remain largely invisible at home and around the world in his first few months in office. As a result, the United States now has a hollow, unempowered, and demoralized diplomatic corps that cannot effectively make its voices heard in critical interagency debates or in discussions with foreign governments. When diplomats’ vital perspectives on both the alternatives to military power and the limitations of using force are missing from policy debates, military options will inevitably seem more attractive than patient statecraft.

Third, the Trump administration has too many generals influencing its thinking on national security. As we noted in a previous article, the Pentagon is deeply in the midst of what we called the oversight gap. While hundreds of Defense Department political appointee slots remain vacant, senior generals are effectively in charge of many of the day-to-day operations in the Pentagon. Furthermore, two of the most important civilian positions in the national security realm (other than the president) are held by military men with battlefield experience in recent wars. Army Lt. Gen. H.R. McMaster is the national security advisor, who sees the president daily and dispenses advice on dealing with every international security crisis. (His chief of staff at the National Security Council is Keith Kellogg, a retired Army three-star general.) And James Mattis retired so recently as a Marine four-star general that he could not be confirmed as secretary of defense until Congress had waived the legal requirement for the person filling that position to have been out of uniform for at least seven years. Both of these posts are purposefully designed to be filled by civilians in order to exert effective civilian control over the military, and to help ensure civilian viewpoints are considered in national security debates. No matter how smart and qualified these two men are, the fact that they have spent their entire careers in the military inevitably shifts the policy debate toward military options and away from diplomatic, political, and economic alternatives.

Fourth, as noted earlier, Trump has now delegated nearly unprecedented decision-making authority to Secretary Mattis and U.S. military commanders in the field. They are now free to make their own decisions about how many troops to deploy to Iraq and Syria, what weapons to use, and the acceptable level of civilian casualties — all matters that previously were subject to interagency reviews in Washington before these major policy decisions were made. While many in the defense world see this as a useful corrective to the Obama White House, which was frequently accused of micromanaging such decisions, Trump’s extensive delegation swings the pendulum too far in the other direction. Interagency reviews, while often painful, ensure that a wide range of strategic factors are considered before a decision to use military force. Absent that process, commanders may make decisions that have strategic ramifications far beyond their operational theaters. Take, for example, the recent decision to use the “mother of all bombs” in Afghanistan. General John Nicholson, the U.S. commander in Afghanistan, called it “the right weapon for the right target” since it was the only weapon capable of destroying the networks of tunnels and caves used by the Islamic State. His military assessment was almost certainly correct. But since it was dropped while U.S. tensions with North Korea were rapidly growing, its use was also seen as a signal to Pyongyang about U.S. strength and resolve — and may have unintentionally escalated that very dangerous confrontation. There is also a more insidious effect of empowering operational commanders to make decisions with strategic consequences. When operations go awry, the president can absolve himself of responsibility — as Trump essentially did after the failed raid in Yemen in which a Navy SEAL was killed. This dangerously undermines civilian control of the military, because it puts senior military leaders in the inappropriate position of making strategic or political decisions that rightfully belong to civilian leaders.

Some would argue that the shift toward a much greater reliance on military power by the Trump administration is actually a much-needed corrective. This view holds that the Obama administration was reluctant to unabashedly employ U.S. hard power, and as a result the world is now a more dangerous place. Yet force alone cannot solve many of the threats and challenges facing the United States, because its effects tend to be both primarily destructive in nature and fleeting. Military power cannot effectively create enduring outcomes without a many-year commitment that is backed up with significant investments in diplomacy, foreign aid, and economic development. Few, if any, of Trump’s initial military forays show any evidence of this integrated approach. Furthermore, the use of force always risks escalating in unpredictable and dangerous ways. So far, Trump’s military operations have targeted relatively weak adversaries where the risks of escalation have been fairly low. But an impulsive U.S. military riposte against North Korea, Iran, or Russia in reaction to a provocation could quickly escalate into a major war that could bring untold levels of death and destruction to friend and foe alike.

Trump should recognize that the use of military force always engenders the significant possibility of escalation into a larger, more prolonged and more deadly conflicts. Wars frequently erupt from miscalculations on both sides, and can rapidly spiral out of control — an especially dangerous risk with nuclear-armed opponents. The serious interagency debates that presidents have typically led before decisions about the use of force are designed precisely to minimize the chances for such miscalculations by carefully considering all other options before war. Trump’s expansive use of military power in his first 100 days has come with few dangerous consequences, further raising its allure. But military power is not a panacea. As he becomes a more seasoned commander-in-chief, Trump must also learn to value restraint and to integrate all of the elements of national power. Failing to see the dangers of the continuing reflexive use of military force will set the nation on a path of grave and unnecessary risk.


Lt. Gen. David W. Barno, USA (Ret.) is a Distinguished Practitioner in Residence, and Dr. Nora Bensahel is a Distinguished Scholar in Residence, at the School of International Service at American University. Both also serve as Nonresident Senior Fellows at the Atlantic Council. Their column appears in War on the Rocks every third Tuesday. To sign up for Barno and Bensahel’s Strategic Outpost newsletter, where you can track their articles as well as their public events, click here.

Image: U.S. Army photo by Rachel Larue