In his foreign policy address following the northeast state primaries Donald Trump outlines a policy with less foreign engagement in trouble spots, and greater reliance on partners in Europe and Asia contributing to joint defense. It also includes building up the military and nuclear arsenal. It criticizes the Bush administration for intervention in Iraq that benefitted Iran, and the Obama administration for policies that led to the rise of Islamic State. Because Trump is not for supporting foreign engagements in trouble spots the difference in Trump's policies is not announcing or signalling in advance what U.S. response would be, instead keeping it unpredictable. It is not clear how much this would work given that any president would inherit the situation before him, and also the complexity of the situation would not change, such as the need to have Iranian cooperation and Saudi cooperation to tackle Islamic State. The Bush administration started with a similiar intention to focus on domestic policy, till the 9/11 surprise attack steered it away towards nationbuilding overseas. The pendulum swung in the latter years of the Bush adminstration to the Iraq intervention, Abu Ghraib and Guantanamo, followed by a swing in the other direction to allowing Libya and Syria disntegrate leading to millions of refugees. Complexity, surprises, and swings of popular opinion, are unlikely to go away, even as caution is exercized and military capabilities enhanced....