Patrick Buchanan is running for president on a platform of gut isolationism. In the test ban treaty rejection, the Senate majority demonstrated its distrust of arms limitation agreements in general. Its members favor reliance on U.S. arms and a new U.S. missile defense system, rather than on treaties, even if building that missile defense wrecks existing nuclear arms limitation agreements. Most Americans are comfortable with the idea of keeping the world at arm's length. The disadvantage is that doing so is bad for business and employment, and arguably for national security as well.
Traditional isolationism is no longer very practical.
However, the lesson of the test ban affair is that while Senate isolationists cannot impose their own policy they can do much damage to mainstream American internationalism. They have done the same thing with their refusal to pay United Nations assessments. This is why the United States has become what might be called a lame duck superpower. It proclaims ambitious global policies and American leadership but increasingly lacks the ability to deliver on its promises. The present administration, or whatever administration follows in 2001, can ask for international cooperation and proclaim American world leadership, but you can't lead the world when the Senate won't ratify the treaties or pay the country's bills.