National sovereignty is not an antonym to alliance. A nation can be sovereign and make great, mutually beneficial alliances with friendly nations. An alternative to cancer is absence of cancer.
I’m not opposed to friendly alliances. I am opposed to entangling alliances,the kind that get us involved in other nations’ wars which don’t involve US national interests. The US,Britain and France didn’t need institutions like the the League of Nations and the UN to win two world wars. But thanks to the UN, Truman,and our State Department we did not win the Korean War and look at the mess we have now as a result. We do not need the UN to get along with other countries.