The new Four Horsemen of the Apocalypse—populism, nativism, isolationism, and protectionism—tend to ride together, and they are challenging the political center.
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Generating support for an internationalist foreign policy requires a president to paint a vivid picture of what that world would be like without an active United States.
It’s a lengthy article. Here is the archived link for those interested.
It’s a long article, but the general point is the United States, while flawed, is very important for maintaining the current world order and preventing despots (such as Putin) from engaging in further wars of conquest.
Trump, being who he is, is the type of President who would enable this sort of situation to occur; he is a populist, protectionist, and isolationist who also hates immigrants.