They know it won't become law. The point is to rile up the media, get hits on cable news, fund raise, and generally be useless as a governing body. This is what both parties do when they are out of power, and I would say is what they _prefer_ to do. It's easier than governing, makes them money, gets them media attention, etc.
Both parties here in the US _want_ to be minority parties so that they can behave this way and assume no actual responsibility for anything.