US troop drawdown in South Korea worth considering

As a second summit between President Trump and Kim Jong Un approaches, concern lingers about what the president may agree to when he meets with the North Korean leader. One primary worry among U.S. and South Korea analysts is that he will offer to reduce the number of U.S. troops in Korea and receive no meaningful concessions from North Korea in return. A U.S. force reduction long has been considered taboo. But if North Korea agrees to credible steps toward denuclearization, a partial reduction of U.S. troops in South Korea — though not a complete withdrawal — should be on the table.

The United States has drawn down troops in South Korea before. In 1954, one year after the Korean War ended in an armistice, there were an estimated 223,000 troops in the country. The number since then has fluctuated but continued a steady downward trend to the current 28,500. There have been four drawdowns of 4,000 troops or more, happening 13 to 21 years apart. It has been 14 years since the last drawdown; the window is open.

{mosads}As these drawdowns have taken place, South Korea has stepped up. For decades, Seoul has been increasing its defense budget in line with its economic development, and its military budget is now the 10th largest in the world. In 2019, it is set to spend $42 billion, an 8.2 percent increase from 2018 and the largest year on year increase in more than a decade.

With an increasingly capable South Korea, amid hardware and technological gains for both countries, the United States must answer the evolving question of what force levels are required to achieve its security goals. U.S. forces in Korea are not expected to single-handedly defeat a North Korean invasion. Instead, they carry the grim “tripwire” moniker, indicating that they are meant to slow down an invasion and amass sufficient casualties in the process to ensure a larger U.S. military response. If the goals of deterring North Korea and responding to an emergency in the region can be met with a smaller U.S. force presence, a partial drawdown makes sense.

In the past, drawdowns have taken place in consultation with South Korea. President Trump, however, has shown through past behavior that he may be open to a complete withdrawal without any significant, measurable concessions by North Korea. Doing so would be a lasting strategic mistake. It would irreversibly damage the U.S.-South Korea alliance, embolden North Korea, and do lasting damage to the U.S. force posture in the region.

A reduction in U.S. troop strength is especially sensitive now as the United States and South Korea recently concluded a new agreement on host nation support. Details have not been released, but early reports indicate South Korea will pay nearly $900 million in 2019, up from $850 million under the previous five-year agreement. This is roughly 50 percent of the total non-personnel costs. Japan pays a similar percentage to base U.S. troops and has been called a model of host nation support.

President Trump had called for South Korea to pay 100 percent of the costs, an unpopular demand for the South Korean public. In that context, a troop reduction could be seen as a punishment for South Korea. That need not be the case.

Throughout the process of reducing U.S. forces in South Korea, deterrence against North Korea remained effective. But previous reductions gained zero concessions from North Korea. If the Trump administration can manage the optics and messaging — major challenges for this White House — it could position a troop reduction as leverage to gain meaningful concessions from North Korea as well as part of reevaluating the global force posture of the United States. In doing so, it could move negotiations with North Korea forward, seek to collect those concessions in the future, and avoid completely wrecking its alliance with South Korea.

Karl Friedhoff is a fellow in public opinion and Asia policy in the Lester Crown Center on Foreign Policy at the Chicago Council on Global Affairs. Follow him on Twitter @KarlFriedhoff.