Increasingly, Southeast Asian states fear that the United States is an unreliable ally. This feeling has been growing since the end of the Cold War. In the 1990s, the US and Southeast Asian clashed over the “Asian values debate” and predatory American actions during the Asian economic crisis. In the 2000s, Southeast Asia was alarmed by growing American imperial overstretch in the aftermath of the wars in Iraq and Afghanistan. The inability of the Obama administration to “rebalance” American foreign policy towards the Asia Pacific was a further cause for concern. Today, the erratic behavior of the Trump administration is adding to regional instability and uncertainty. A security vacuum is opening in Southeast Asia. China wants to fill this vacuum, but it is distrusted in the larger region. The Association of Southeast Asian Nations (ASEAN) sees one of its purposes as shaping the regional security environment. Can it fill the hole left by the changing American regional role?