Have Democrats found the issue on which they can break what’s left of Senate traditions and parlay a 50-50 split into partisan domination? It’s far from clear that anything will be enough to move the two recalcitrant members of their caucus — Sens. Joe Manchin, D-W.Va., and Kyrsten Sinema, D-Ariz., — to change their minds about voting to change the chamber’s rules that require a majority of 60 in order to invoke cloture and end filibusters. But if anything will do it, it might be the claim that passing their game-changing federal voting rights bill is the only way to defend American democracy against Republican insurrectionists.

Manchin and Sinema’s opposition was the rock on which the Biden administration’s effort to pass their trillion-dollar “Build Back Better” spending bill broke in December. The pair felt comfortable resisting presidential pressure as well as a storm of abuse from leftists on legislation that would likely sink an already shaky economy and ......