"What are you prepared to do?"
--Jim Malone (The Untouchables)
A couple of days back marked the 80th anniversary of the repeal of Prohibition. Prohibition was legalized by the 18th Amendment which was ratified in 1919. It was reversed by the 21st Amendment ratified in 1933.
The repeal of Prohibition teaches a couple things. One is that bad law, law that opposes the natural rights of human beings, never lasts. From the day bad law is passed, forces of nature work against it until the law is inevitably thrown off.
Second is that laws enacted in ways that make them difficult to reverse can still be repealed. This holds true even for constitutional amendments.
Amending the Constitution of the United States requires: a) a proposal by either Congress or a constitutional convention assembled at the request of at least 2/3 of the state legislatures, b) congressional proposals require a super-majority 2/3 of the membership in each house, c) ratification by at least 3/4 of the states either by their legislatures or by ratifying conventions.
This is a high hurdle for any proposed amendment to clear. If an amendment does clear this hurdle, then it seems nearly impossible to reverse the process to take that amendment off the books.
But the repeal of Prohibition demonstrates that it can still happen. Bad laws, even sweeping, 'signature' ones, can be undone.