Joe Biden is supposed to know something about legislating. After all, he spent 36 years in the U.S. Senate. He must have learned something in those decades. And yet Biden is the driving force behind one of the biggest Capitol Hill fiascos in years: the rapidly imploding “deal” on the U.S.Mexico border, plus aid to Israel, Ukraine and Taiwan. It was Biden who insisted that those disparate subjects be linked -- he threatened to veto any part that was passed alone -- which turned out to be a fatal mistake given the impossibility of a majority in Congress agreeing on any immigration-related topic. Failing to agree on immigration guaranteed failure on the other policies.