WASHINGTON — Led by loyalists who embrace former President Donald J. Trump’s baseless claims of a stolen election, Republicans in state legislatures nationwide are mounting extraordinary efforts to change the rules of voting and representation — and enhance their own political clout.

At the top of those efforts is a slew of bills raising new barriers to casting votes, particularly the mail ballots that Democrats flocked to in the 2020 election. But other measures go well beyond that, including tweaking Electoral College and judicial election rules for the benefit of Republicans; clamping down on citizen-led ballot initiatives; and outlawing private donations that provide resources for administering elections, which were crucial to the smooth November vote.

And although the decennial redrawing of political maps has been pushed to the fall because of delays in delivering 2020 census totals, there are already signs of an aggressive drive to further gerrymander political districts, particularly in states under complete Republican control.

The national Republican Party joined the movement this past week by setting up a Committee on Election Integrity to scrutinize state election laws, echoing similar moves by Republicans in a number of state legislatures.

Republicans have long thought — sometimes quietly, occasionally out loud — that large […]