Trump has what I would consider to be mental problems, but the country as a whole has been acting stupidly in several areas, among them the refugee and Muslim immigration questions. Assuming Trump does not nuke Denmark or France or Syria, I would find it hard to imagine that he would make anything worse. He is a negotiator and tries to find ways to make a deal with people. Most everybody at this point, on both the left and the right, do not believe we have had any foreign policy victories in the Obama administration other than, perhaps, the deal with Iran which Congress never approved as a treaty. Libya, Syria, Iraq and some other countries are all in much worse condition now than 8 years ago. Whether that is the fault of American policy or other factors, we don't really know, but other than carpet bombing civilians and creating some even newer group other than ISIS and the Al-qaeda affiliate called Al-Nusra that wants to make war on us, what foreign policy situations could be worse than what we have? Nuclear war with China over some islands?
What is more, some people allege that the way the Iran deal as written it violates the law and this includes one law signed by Obama himself. Negotiating treaties that are never ratified and which themselves require or create violations of federal law are likely to have problems as soon as someone notices and acts upon the problems.
As a person who values honor and integrity, what are the results you might expect from a deal that is not ratified as a treaty and that allegedly includes or requires violations of US federal which is not repealed?
David