Who whips up that fervor, the war on drugs wasn't started as a grass roots campaign, for sure, it came from the top
Most often, it's the people who either need A Cause to get elected, or want to use a particular mob cry to funnel money to businesses in their constituency and get kickbacks (sorry, campaign contributions). The old hereditary House of Lords (before they abolished most of them and stuffed the house with Labour cronies followed by Tory cronies) had the advantage that, aside from a few issues like inheritance tax and fox hunting, the members didn't really have much of a vested interest in anything. If you watched the debates, the contrast between the two houses was astonishing. The Commons was full of people trying to score points against the other party, the Lords was almost empty, but those there were having an intelligent debate on the issues in the legislation.