Posted: Jul. 18, 2017 11:45 am

THE Supreme Court will consider this fall whether gerrymandered election maps favoring one political party over another violate the Constitution, and the outcome could affect elections across the country.

Justices will decide whether Republican lawmakers in Wisconsin drew electoral districts so out of step with the state's political breakdown that they violated the constitutional rights of Democratic voters. A federal court struck down the state Assembly boundaries as unconstitutional in November.

There's no way to guarantee that when voters are divided into districts, the party that gets a majority of overall votes will win the majority of seats. But when the party that drew the map is practically guaranteed a legislative majority, it devalues the votes of the people who are locked into a permanent minority.

Moreover, the more certain it is that whoever wins a certain party's primary will be elected, the less the general election matters.

Clearly, there will be some safe districts almost no matter how lines are drawn. But when government officials intentionally draw a biased map, they are deliberately discriminating against the members of the other party.

The Associated Press recently analyzed the results of U.S. and state House elections last fall across the nation, examining the percentage of races lacking major-party opposition and calculating state partisan advantages using a statistical method designed to detect potential political gerrymandering.

In Missouri, the AP found the amount of partisan advantage favoring Republicans was fairly typical compared with other states. But Missouri ranked in the top tier of uncompetitive states, with nearly 60 percent of its 163 state House winners lacking a major-party opponent.

That represented a spike from about 50 percent uncontested races in the prior two elections and about 40 percent during the first decade of the 2000s. For GOP Rep. Craig Redmon of Canton and Democratic Rep. Gail McCann Beatty of Kansas City, for example, 2016 marked the third straight general election in which they were the only choice on the ballot.

In Illinois, 72 of 118 state House races had just one major-party candidate in the 2016 elections, or 61 percent. Democrats won 67 of those seats to maintain an advantage that, aside from two years in the early 1990s, they have held for decades.

Voters in Illinois' old 17th Congressional District remember the torturous boundaries that ran from the Quad Cities down the Mississippi River to Adams County, then east through a sliver of Springfield and on to Decatur. Contiguous it was not, but it benefited then-Democratic U.S. Rep. Lane Evans.

The Supreme Court has never struck down legislative districts because of unfair partisan advantage, although it has intervened frequently in disputes over race and redistricting over the past 50 years. The challenge for justices now should be to set a principled limit to political gerrymandering.

The impact of their decision may extend beyond Election Day. If representatives focus on winning primaries instead of convincing the broader electorate, that could contribute not only to ideological extremism, but also to a lack of respect and concern for all American voters.