Virginia Gov. Terry McAuliffe (D) may call a special legislative session in August on the state’s congressional district boundaries. (Steve Helber/Associated Press)

THE 3RD congressional districts in Maryland and Virginia are roughly 200 miles apart — depending on which part of their ungainly boundaries one takes as a starting point — and, on the surface, seem to have little in common. Virginia’s 3rd stretches from Norfolk to Richmond. Maryland’s 3rd, with contours often likened to a blood spatter, incorporates parts of Baltimore City, as well as parts of Anne Arundel (including Annapolis), Baltimore, Howard and Montgomery counties.

What they share is a genesis in bald-faced gerrymandering contrived by politicians intent on manipulating electoral maps to their advantage by hand-picking their own voters. Democrats are the culprits in Maryland’s case; Republicans did the deed in Virginia.

Encouragingly, there are signs that the jig may be up, or that at least it is facing more pressure than ever before.

Prodded by the judiciary, Virginia’s Democratic governor, Terry McAuliffe, and Maryland’s Republican governor, Larry Hogan, are moving toward some version of redistricting reform. In both cases, that would be a blow to the good-old boys in the state capitals and Congress, and a favor to voters, whose say in elections has been subjugated to partisan interests.

Both Mr. McAuliffe and Mr. Hogan are on record as backing redistricting reform to minimize political shenanigans when their state legislatures redraw electoral lines after each decennial census. Each faces a state legislature dominated by the opposing party. And each can convincingly make the argument that the timing is right to shift the responsibility of drawing electoral maps to a bipartisan or nonpartisan commission.

In Virginia, a federal court has ruled twice, most recently last month, that Republicans drew the state’s 3rd Congressional District unconstitutionally, packing it with Democratic-leaning minority voters. The effect was virtually to ensure that surrounding heavily white districts would remain safely in Republican hands. (It’s no coincidence that while Democrats have won every statewide race in the commonwealth since 2009, as well as the presidential contests in 2008 and 2012, the GOP controls eight of the state’s 11 congressional seats.)

The court ordered that Virginia’s congressional maps be redrawn by Sept. 1, and Mr. McAuliffe has said he will call a special session of the state legislature to do so next month. But GOP lawmakers, afraid that a fairer map will mean the loss of one or more Republican seats in Congress, are playing for time, hoping a higher court will grant them a reprieve. Let’s hope the courts do not.

In Maryland, it’s the Democrats, long dominant in Annapolis, who have played unconscionable games with electoral maps for years. A casual glance at the state’s meandering, tortuous 3rd District, which squiggles its way through four sprawling counties, is a testament to that arrogance and a study in political cynicism.

Now advocates for redistricting reform in Maryland, heartened by a Supreme Court ruling last month empowering voters to fight back against gerrymandering, are pressing Mr. Hogan to name a task force that would recommend the establishment of a bipartisan or nonpartisan redistricting commission. It’s critical that he do so quickly, so that the next state legislative session, which begins in January, is presented with recommendations before time slips away and voters are once again treated with contempt by their elected representatives.