The Supreme Court (J. Scott Applewhite/AP)

Let's get one thing straight: When given the chance, both parties have drawn congressional and state legislative districts in a way that lets their side hold power.

But lately, Republicans have been on the receiving end of judiciary blows to their congressional and state legislative maps across the country.

They caught a big break when, on Monday, the Supreme Court essentially declined to weigh in on two partisan gerrymandering cases that could have given Democrats a road map to knock down even more GOP-drawn maps across the country.

The Supreme Court in effect declined to say whether GOP lawmakers in Wisconsin and Democratic lawmakers in Maryland unconstitutionally drew overtly political districts, though justices left the door open for future challenges to partisan gerrymandering.

Had the Supreme Court decided that, yes, lawmakers in either or both these states unconstitutionally weighed partisanship to draw electoral lines, it would have been a historic decision — the first time ever the court used measures of partisanship instead of race to knock down electoral maps as unconstitutionally gerrymandered.

Republicans controlled the pens in a majority of states where legislatures got to draw the districts after the 2010 Census. So Republicans would have been most vulnerable to such a game-changing decision by the Supreme Court about how districts can be drawn. Democrats were hoping to use the Wisconsin and Maryland models to sue Republicans in states like Ohio and Florida.

All of this would have been happening just before the 2018 and 2020 state and congressional elections, an absolutely critical deadline for Democrats.

Democrats need to win back as many state legislatures as they can by 2020 to control the map-drawing process in more states. The 2020 Census release is the next time electoral maps will be redrawn to match current populations.

Democrats are in such a hole in state legislatures that there is a real chance they will be locked out of the map-drawing process — and thus locked out of power in Congress and a number of states — for another decade.

Court rulings against GOP-drawn districts looked like a promising shortcut.

In Pennsylvania this year, the state's highest court forced Republicans to redraw their congressional maps after deciding Republicans had unconstitutionally considered voters' politics to draw lines. The decision has given Democrats the chance to pick up as many as half a dozen congressional districts in November, a huge gain in their efforts to take back the House majority this November.

A federal court in North Carolina struck down the GOP-drawn congressional maps, saying Republican lawmakers violated the Constitution by drawing them to heavily favor Republicans. Stephen Wolf with the liberal politics blog Daily Kos estimated that a nonpartisan map in North Carolina could give Democrats anywhere from two to five more seats in Congress. Republicans are appealing that decision to the Supreme Court.

And the Supreme Court did not totally shut the door on deciding whether partisan gerrymandering is constitutional.

As Rick Pildes, an expert on redistricting law at New York University explains, the justices left open the possibility that Democrats in Wisconsin could go back to the drawing board and try to prove, district-by-district, that Republicans unfairly used politics to draw the boundaries. That case in North Carolina, in which Democrats argue that each individual district is gerrymandered, could make its way to the Supreme Court.

And Justice Elena Kagan suggested in Monday's ruling there could be an opening for challengers to argue their First Amendment rights have been violated by having districts sliced and diced and pieced together in eyebrow-raising ways to benefit one party.

“Courts — and in particular this court — will again be called on to redress extreme partisan gerrymanders,” Kagan wrote. “I am hopeful we will then step up to our responsibility to vindicate the Constitution against a contrary law.”

All of that could take months or years to come to fruition. For now, partisan gerrymandering is constitutional under the eyes of the highest court in the land. And because Republicans were the ones in power the last time parties got to draw the maps, they are the ones who caught the biggest break Monday.