Last week the U.S. Supreme Court heard arguments in the second of two lawsuits that challenge partisan gerrymandering — the time-dishonored practice of drawing legislative district lines to give one political party an unfair advantage. Wednesday’s argument involved a map engineered by Maryland Democrats to unseat a Republican congressman. In October, the court heard a challenge to a Wisconsin legislative map engineered by Republicans to disadvantage Democrats.

Now that the second act of this legal drama has been played out, the justices should move toward a decision holding that the Constitution prohibits congressional and legislative maps that are clearly designed to entrench one party and dilute the votes of the other. Such a ruling would strike a blow for representative government.

For the court to reach that result, it needs to keep its collective eye on the big picture and not be waylaid by the sort of quibbles and qualms featured in last week’s argument.

There was a clarifying moment in the often technical argument when Justice Stephen G. Breyer succinctly stated the issue in this case. “It seems like a pretty clear violation of the Constitution in some form to have deliberate, extreme gerrymandering.”

Unfortunately, Breyer then went into worry mode and wondered whether there was a practical solution “that won’t get judges involved in dozens and dozens and dozens of very important political decisions.” Finally, he suggested that because of the complexity of the issue the court might want to put off a decision and schedule new arguments on the Maryland and Wisconsin cases and address a redistricting dispute in North Carolina at the same time.

That would be a mistake. The court has been agonizing about how to manage partisan gerrymanders for two decades. It should stop its dithering and deal a death blow to the gerrymander.