Nathaniel Persily, a Stanford University law professor and elections scholar, said what was going on reflected a shift from a belief in shared rules of democracy toward one that sees elections as struggles for power “in which you need to push up against the rules to win.”

He added, “We’ve reached a situation in which the fight over the rules and who gets to vote is seen as a legitimate part of electoral competition.”

Republicans consistently say restrictions on registering and voting are needed to combat election fraud, a view most prominently expressed in President Trump’s widely derided statement, with no evidence, that millions of illegal voters cost him the popular vote in 2016. Studies regularly conclude that fraud is exceedingly rare; a New York Times survey of 49 state election offices after the 2016 general election found no allegations of widespread fraud, and no fraud claims at all in 26 states.