You would rather get sick to death waiting until they're crossing our borders first, I guess. You buy the stupid claim that the U.S. is the root of all evil n stuff and the rest of the world are just hapless victims, just hippies minding their own business and hobbit like. Thomas Jefferson thought that too, but got a wake up call and had to face the fact the rest of the world will not go along with any country being neutral and minding its own business and stuff.
It is much cheaper and more effective to deal with foreign aggressors overseas than here, and much more effective to deal with them before they increase their powers. If FDR could have had his military budget when he wanted it and shut down Hitler and Mussolini, many millions of lives would have been saved with early and decisive intervention. Early intervention in WW I would have done the same, and possibly prevented WW II. Truman's containment policy saved millions of lives. Eisenhower's policies were more conservative but also still saved millions. LBJ's policies in Viet Nam, Africa, and the ME led to the bankruptcy of the Soviet Union in 1973.
Today, isolationist rubbish has led to Red Chinese aggression, Putin's invasions and nuclear threats from Iran and North Korea as well, long with making kidnapping of Americans a popular and lucrative hobby for all of these shitholes and more. Congratulations on that achievement. Sooner than later it wil get a lot more people killed, including Americans.