I wonder if they want him to, since so many of them support it. This would take the heat off them, they must think. I wouldn’t put collusion past them anymore.
This is a tried and true way to avoid responsibility: the congress has done this with many issues, from Abortion to the Federal Reserve they let others implement the ideas that are too toxic for them to touch and then claim that it's the other branches job/responsibility and that they just can't do anything.