A “wedge issue” is one that splits a political base. It’s exploited by the opposition.
For example, blacks oppose gay marriage more than other democrats. If a politician were able to target blacks highlighting the Dem support for it, that would be using a “wedge issue.”
In politics, a wedge issue is something you use against your opponent and try to keep them from using against you.
The first time I ever heard the term was years ago, and it applied to partial-birth abortion. The issue was used to divide the Left on the larger issue of abortion itself. The reasoning was that if you could appall people enough at PBA, they would sense, if only dimly, that all abortion was slaughter.
Gay marriage could possibly be used to divide the straight middle who do not care that much about gay marriage from the militant gays and their supporters, who do want it. A smaller issue used to divide a larger one, the larger one being support for the gay agenda in general.
It’s a sharp issue that separates the thinkers from the straitjacketed lefties.
Your last paragraph makes no sense at all. How could something like partial-birth abortion be used to divide pro-lifers? It’s the part of the issue they would be most vehement about supporting! Wedges are only sharp at one end.
I see the language getting dumbed down all the time. Back in the sixties, Bill Kunstler exhorted his followers, “Right on!” Meaning they should continue the fight right onward without stopping. Now it is used to mean the equivalent of the British “spot on”: “you are exactly right!”
Let’s remember what a wedge issue actually is. Then maybe we have a chance of using it effectively.