Gov. Larry Hogan took an important step toward fulfilling one of the most important promises of his campaign today by naming a commission to come up with recommendations to reform the process by which Maryland redraws congressional and legislative district maps. Granted, he made a lot of important promises, like boosting Maryland's economy and setting the state's taxation and fiscal policy on a permanently sustainable course. But this one stands out because his administration is in a position to deliver on a fundamental reform for the cause of good government in a way that might never have happened if he hadn't been elected.

Maryland's redistricting process is dominated by the governor, and for the last several decades, that has meant, for all practical purposes, that the lines have been drawn by a small group of Democratic insiders in a way that benefits the Democratic Party. After the 2000 census, then-Gov. Parris Glendening redrew the lines to shift Maryland's House of Representatives delegation from a 4-4 split between the parties to a 6-2 advantage for the Democrats. After the 2010 census, then Gov. Martin O'Malley's redistricting set the stage for Democrats to take seven of the eight seats. So long as Democrats were firmly in control of both the governor's seat and the legislature, there was no reason for anyone to listen to the complaints from good government types about contorted district lines. Allowing politicians to choose their voters rather than the other way around suited the powers-that-be just fine.

But with Governor Hogan, Democrats must face the legitimate possibility that a Republican could still be in control come 2021 — and that he could do unto Democrats what Democrats have done unto Republicans. Mr. Hogan's Democratic opponent, Anthony Brown, also promised redistricting reform, but had he been elected, Democrats in the legislature wouldn't necessarily have cooperated even if he had followed through. But with Mr. Hogan in charge, they have every incentive to pursue real reform.

And although Mr. Hogan didn't endorse a specific path at his news conference today , he provided about as tangible a signal as possible that he's interested in doing more than futzing around the margins of Maryland's law. He named his appointees to a redistricting commission and said it would study other states that have established independent, non-partisan bodies to redraw district lines. Moreover, he said the group would be charged not only with issuing a report but also with drafting language for a constitutional amendment on congressional and legislative redistricting. It's not a question of whether he will be pushing for major reform but of what shape it will take.

The governor's appointees to the board reiterate the point. He named as co-chairs a Democrat and a Republican, and he included representatives of organizations across the political spectrum that have been critical of the way Maryland redraws its legislative maps, including Common Cause, the League of Women Voters, the Maryland Public Policy Institute and the NAACP. That boosts the odds that he can hold together a coalition of progressives and conservatives to push reform through the legislature in time to put an amendment on the ballot next year.

Other states have provided various models for how to draw district lines in a way that fosters the "transparency, fair representation, and election integrity" Governor Hogan set as goals. Maryland should cull from them a system that allows substantial public input; vests decisions in a body that is not controlled by either political party; requires lines to respect community boundaries (currently a requirement for state legislative districts but not congressional ones); and disregards incumbency as a factor in determining district lines.

Senate President Thomas V. Mike Miller dismissed Mr. Hogan's effort, saying gerrymandering is a national problem and that he did not want to put Maryland at a disadvantage compared to other states. Baloney. He doesn't want to put the Maryland Democratic Party at a disadvantage to gerrymander-happy Republicans in states like North Carolina and Texas. And the fact that Maryland voters did not reject the current, contorted congressional district maps when they had a chance in 2012 doesn't mean anything either. The referendum as written asked voters whether they wished to approve or reject a law that "establishes the boundaries for the state's eight United States congressional districts based on recent census figures, as required by the United States Constitution." It's a wonder that 36 percent of the state was able to see through that mom-and-apple-pie wording to understand what they were really voting on.

Conservatives in the legislature have long been angry about Maryland's redistricting process. After 2012, progressives are embarrassed by it. Now we've got a governor who wants to do something about it. Mr. Miller can fight it, but redistricting reform is an idea whose time has come.