This Chapter challenges the prevailing view of much recent use of force scholarship in the United States that supports the use of a self-defense exception to justify U.S. military action all over the world since 9/11, arguing that instead the traditional framework of the U.N. Charter provides the appropriate legal framework. The Chapter notes the slide by U.S. Presidents since 9/11, including Barack Obama, into increasingly aggressive and unmoored understandings of constraints on jus ad bellum rules, and the tendency of the current U.S. President, Donald Trump, to threaten to — and use — force unlawfully in violation of international law and with potentially catastrophic consequences. The Chapter takes issue with scholars arguing that this "perpetual war" is now the new standard and discusses efforts to push back against this slide into unlawfulness including the activation of the aggression amendments of the International Criminal Court Statute, and the adoption of a new treaty banning the use and possession of nuclear weapons, which opened for signature on September 20, 2017.