Good point illustrating how to work to defuse a wedge attempted against you. Find what's common to all the possibly wedge-able factions and unite behind that banner.
Or just simply unite when we have a candidate, which didn’t happen last time and we are forced to watch our culture and government be dismantled piece by piece.
I still think it is helpful to use “wedge” for a creatively designed small issue that rends the fabric of a bigger issue for the other side, and just keep the phrase “dividing the opposition” for big sledgehammer type attacks. But I am one of those people who hate to see the fine distinctions in the English language get smooshed, especially those that are so useful in politics.