Key points Observers and practitioners are frequently frustrated at the level of defense burden-sharing in U.S. alliances—alliance members’ contributions to collective defense objectives—and particularly at allies’ low level of investment in their own defense. This paper compares two approaches to soliciting burden-sharing in U.S. alliances: retrenchment and conditionality. Retrenchment refers …

President Donald Trump recently informed Benjamin Netanyahu’s government in Israel that he intends to withdraw the 2,000 U.S. troops stationed in Syria to combat the remnants of Islamic State, according to Israeli media. If true, that news is sure to stir the pot in Washington, where Trump’s pledge to remove …

The fall of the brutal Assad regime marks a critical opportunity for the United States to remove itself entirely from Syria, avoiding entanglement in further war. American troops have been in Syria for the past decade with the primary objective of defeating the Islamic State in Iraq and Syria (ISIS), …