The Trump administration is considering U.S. retrenchment from Europe and possibly elsewhere. There are competing claims about the potential effects of reducing U.S. military involvement abroad.
To better understand the potential trade-offs, a new RAND report explores four cases of limited U.S. retrenchment in the 1960s and 1970s, examining how West Germany, South Korea, Japan, and Taiwan responded to shifts in Washington's strategy.
These four allies tended to react to U.S. retrenchment by increasing their defense spending, working more closely with regional partners, moderating their foreign policy goals, and maintaining alignment with the United States. One ally, South Korea, initiated a nuclear program that Washington opposed. (Seoul eventually abandoned the program under intense U.S. pressure.)
What does this mean for today? If future U.S. policy shifts are similar to those of the past, then they could produce similar effects. More dramatic changes, on the other hand, could produce different outcomes.
It’s also worth noting that modern-day U.S. allies are more economically intertwined with China than allies were with America’s Cold War rivals several decades ago. This raises the possibility that retrenchment could have different effects on allies' alignment choices.
This analysis reveals a few recommendations for U.S. policymakers considering retrenchment:
- Manage allies’ opposition to retrenchment while incorporating their input about implementation.
- Don’t expect limited retrenchment to be a one-size-fits-all way to improve burden-sharing. (Effects can vary based on each ally’s characteristics.)
- Weigh nonproliferation against burden-sharing goals.
