In the coming weeks, high federal courts will hear important cases challenging two ways Republicans have sought since Barack Obama’s election as president to restrict voting of Democratic-leaning groups.


They come at a time when efforts initially focused on restrictive voter-identification laws in Texas and other GOP-controlled states have broadened to include purging voter rolls of people who hadn’t lately voted and limiting early voting in areas with large minority populations.


In early December, a federal appeals court will hear the latest version of the long-pending Texas voter ID law. In January, the Supreme Court, which is already considering a Wisconsin case challenging political redistricting, will hear an Ohio case that could produce a crucial legal judgment on the ability of state officials to purge voter rolls.


The two cases exemplify how — a half century after the Voting Rights Act democratized elections — voting-rights advocates are on the defensive, fighting moves that would make voting harder, especially for those more likely to vote Democratic. After this month’s resurgent Democratic performance in Virginia and other states, such efforts may well intensify.


The most potentially serious long-term threat to voting rights may stem from the commission appointed by President Donald Trump. Its domination by longtime voter fraud alarmists and its secretive procedures recently prompted a lawsuit against it from one of its own members, a Democrat who contends he has been cut out of its plans and information.


The federal court suit by Maine Secretary of State Matthew Dunlap, one of three Democrats on the 11-member commission, accused it of violating a federal law requiring transparency, contending he and other commissioners “have been deprived of access to documents prepared and viewed by other commissioners.”


Trump created the panel to probe his unproven claims that fraudulent votes caused Hillary Clinton’s 3 million popular-vote margin in 2016. Chaired by Vice President Mike Pence, it’s dominated by Kansas Secretary of State and GOP gubernatorial candidate Kris Kobach, who has spent considerable effort trying unsuccessfully to find and prosecute voting by illegal immigrants.


Its only public hearing in September aired unproven allegations that voters with out-of-state driver’s licenses illegally provided New Hampshire’s small 2016 Democratic margins, though such votes were legal under state law.


Critics say one target is the fact — unchallenged by voting-rights supporters — that the nation’s voter rolls are bloated with people who have moved or died, despite scant evidence of any significant illegal voting. According to the U.S. Election Assistance Commission, created to manage a 1993 law to make registration easier, some 70 million registered voters did not go to the polls in 2016.


Rights advocates also fear the panel will recommend allowing states to require proof of citizenship, something the Supreme Court ruled in 2013 is not allowed. Many poorer Americans just don’t maintain such proof.


The panel seems to be working in tandem with the Justice Department, which has asked state election officials to show what they are doing to maintain accurate registration records, and some private groups like Judicial Watch, which recently sued Kentucky to “clean up” its voter rolls.


Under the 1993 law, state officials can’t remove nonvoters from the rolls unless they fail to respond to a notice seeking affirmation they have moved. An appeals court ruled that Ohio violated the law by using the failure to vote as a “trigger” for sending notices and, in turn, removing voters.


A Reuters study determined Ohio voters were “struck from the rolls in Democratic-leaning neighborhoods at roughly twice the rate as in Republican neighborhoods,” especially in metropolitan “neighborhoods that have a higher proportion of poor, African-American residents.” Democrats are challenging GOP-sponsored purges in Georgia and Florida with similar patterns.


In Indiana, the Indianapolis Star found Republicans helped their party by reducing early voting stations in predominantly Democratic Marion County and increasing them in GOP-voting Hamilton County.


The revised Texas law will go before the 5th Circuit Court of Appeals, which rejected an earlier version as discriminatory, 9-6, with four Republicans joining five Democrats in the majority. U.S. District Judge Nelva Gonzales Ramos ruled the revised law still discriminates against minorities and poor people, who are less likely to have photo IDs than the national average and more likely to vote Democratic.


Meanwhile, two studies of last year’s Wisconsin voting concluded voter ID laws discriminate against Democratic-voting minorities. The most recent, a survey of nonvoters by two University of Wisconsin political scientists, concluded its law prevented 2016 voting by at least 17,000 voters — and probably more. Trump defeated Clinton there by 22,748 votes.


The pattern is clear: Republicans, fearful of expanded voting in an increasingly diverse country, are using questionable legalities to make it harder. Democrats, who believe they have justice on their side and also would benefit, are fighting them.


The result could affect the 2018 and 2020 elections and many to come.


Carl P. Leubsdorf is the former Washington bureau chief of the Dallas Morning News. Readers may write to him via email at: carl.p.leubsdorf@gmail.com.