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U.S. soldiers seen from behind saluting, with a cargo plane in the background. U.S. Army soldiers salute as vehicles carry what are believed to be remains from American servicemen killed during the Korean War, Osan Air Base, Pyeongtaek, South Korea, July 27, 2018 (AP photo by Ahn Young-joon).

U.S. Security Policy in the Trump Era

Friday, Dec. 18, 2020

When President Donald Trump entered office under an “America First” banner, it seemed to herald a new era of U.S. isolationism. As he prepares to leave the White House on Jan. 20, though, the shifts in America’s military engagements during his one-term presidency have been less dramatic than anticipated. Though their numbers are down, U.S. troops are still stationed in Afghanistan—for now. And instead of operating around a clear security strategy, Trump’s tenure was marked by its unpredictability—dramatic reversals, erratic interventions and the fraying of long-standing alliances.

Trump’s isolationist instincts came into regular tension with his closest advisers, many of whom espoused a more traditional view of American power projection. This was never clearer than in December 2018, when Trump ignored his aides and announced his decision to pull all U.S. troops out of Syria, prompting then-Defense Secretary Jim Mattis and other high-ranking officials to resign in protest. Trump subsequently softened his rhetoric, without definitively articulating a final policy, contributing to the sense of uncertainty over America’s security policymaking. The entire process was repeated in October 2019, only this time the decision triggered not resignations, but outrage among even Trump’s closest Republican supporters in Congress.

Meanwhile, Trump’s vision didn’t stop his advisers from hinting at military intervention as a path to regime change in places like Venezuela and Iran. In the latter case, Trump subsequently made his opposition to war clear. His broader reluctance to commit U.S. forces to another major conflict in the Middle East played a part in the deescalation of tensions with Tehran in January, following the U.S. killing of a top Iranian military commander, Maj. Gen. Qassem Soleimani, and Iran’s retaliatory ballistic missile strike against U.S. forces stationed in Iraq.

Over the course of his four years in office, Trump’s America First agenda has actually taken its heaviest toll on long-standing alliances. While he has taken credit for moderate increases in European defense spending, it has come at a cost. His vocal criticisms of NATO have weakened the alliance’s cohesion, and his demands for increased burden-sharing by South Korea and Japan for U.S. forces based in those countries have also strained relations with both Seoul and Tokyo.

There have also been some significant and perhaps durable shifts. The administration positioned economic security as central to national security and justified its increasing use of tariffs on those grounds. Immigration, particularly along the border with Mexico, became a key focus of the security agenda. And Washington has pulled back from counterinsurgency efforts, even as the Islamic State regroups as a terrorist movement. While President-elect Joe Biden is certain to adopt a dramatically different approach on these issues, he will find it harder to ignore them.

WPR has covered the U.S. military and its security strategy under Trump in detail and continues to examine key questions about what will happen next under a Biden administration. Did Trump’s decision to kill Soleimani reestablish deterrence against Iran? Will the shift away from counterinsurgency allow ISIS to reemerge as an insurgency? And how will Biden reestablish trust among U.S. allies while still holding them to their burden-sharing promises? Below are some of the highlights of WPR’s coverage.


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Our Most Recent Coverage

The Dangers of Trump’s Hasty Troop Withdrawal From Somalia

President Donald Trump ordered the withdrawal of American troops from Somalia last week, part of a broad, last-minute push to reduce America’s military footprint overseas. But the drawdown will complicate Somalia’s campaign against al-Shabab, al-Qaida’s resurgent affiliate in East Africa.

U.S. Security Strategy Under Trump

The Trump administration’s security policy was deeply conflicted, torn between the president’s impulse for isolationism and protectionism, the interventionist beliefs of members of his administration and the traditional views of the Washington national security community. The result has been a halting and at times contradictory policymaking process and incoherent messaging. Trump also tried to shift the national security debate from foreign threats to perceived risks at the U.S. border—with some success.

Military Interventions and Withdrawals

Trump entered office promising a new era of American isolationism. Instead, he has maintained troop levels abroad at nearly the same level as his predecessor, Barack Obama. Though he avoided starting any new wars, he brought America to the brink of a conflict with Iran, first dispatching thousands of additional troops to the region to counter Iranian aggression and then assassinating Soleimani in January. He also offered to intervene militarily to help oust Venezuelan President Nicolas Maduro. Meanwhile, he has reversed every drawdown he has announced, including twice backing away from promises to pull U.S. troops from Syria.


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Military Alliances and Partnerships

Trump repeatedly attempted to shake up traditional U.S. military alliances. He criticized NATO allies and announced plans to withdraw U.S. troops from Germany, while making a similar threat against South Korea. Meanwhile, Trump has doubled down on America’s traditional partnerships in the Middle East.

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Editor’s note: This article was originally published in May 2019 and is regularly updated.