Would-be Trump and Johnson voters would do well to listen
All of that is, of course, common sense. Yet from the far Left through the Ron Paul movement and Pat Buchanan, and now to Trump and Johnson, the discredited idea that isolation from the world in the modern era is even an option for America continues to be popular in certain circles which still haven't learned the lessons of World War II. Unpopular, long and costly wars, the expense of foreign aid, and the unpopularity of America throughout the world give the "America First" impulse a certain amount of attractiveness. Yet as the Obama era demonstrates, America will be hated no matter what; the most powerful nation in the world is always hated. And as history and common sense make clear, our security and that of the world depend on our remaining the most powerful country on Earth. For all the rhetoric to the contrary, were America to actually renege on its commitments and leave the world to its own devices, many of the same countries which are so scornful about American power would be the first to complain.
Yet isolationism remains popular on the fringes of the American political spectrum. As Gen. Mattis points out, our continued safety and the security of the world depend on it never becoming American policy.