The Supreme Court’s decision to hear Gill v. Whitford — a case that claims Wisconsin’s congressional districts are unfairly drawn to favor Republican candidates — has people all over the country speculating about whether partisan gerrymandering will finally be ruled unconstitutional. Democrats are excited because current congressional maps are drawn to favor the GOP. But their optimism may be misguided: History shows that redistricting is an inherently partisan process. No matter what standards the court establishes, the people drawing congressional maps will quickly figure out how to give their candidates an advantage while technically complying with the court’s guidelines.

While Democrats think it’s possible to take back the House in 2018, victory would be short-lived, because Republicans are firmly entrenched in state legislatures. If Democrats hope to control Congress and the national agenda in the long-term, they need to win races at the state level, regaining control of state legislatures.

When the courts declared racial packing unconstitutional, Republican lawmakers didn’t change their behavior; they simply changed tactics.

In the Wisconsin case, the Supreme Court may rule on whether partisan gerrymandering is unconstitutional. Seeing as the court traditionally has decided gerrymandering cases using primarily racial considerations outlined in the Voting Rights Act of 1964, this would be an important departure. The VRA established a requirement that states draw congressional districts so that African-Americans and other minority voters can elect their preferred representatives — which was vital for ensuring fair representation for everyone. But the VRA also created a new problem: Politicians began cramming minority voters into as few districts as possible.

When the courts declared racial packing unconstitutional, Republican lawmakers didn’t change their behavior; they simply changed tactics. Republican defendants in a recent North Carolina case argued that their districts were legal, for example, because they were not trying to draw their maps using racial considerations. They were instead trying to draw their congressional districts for partisan political gain, which they believed was OK. Translation? They figured that because the court won’t let us use race as a dominant factor, we’ll use other criteria to achieve the same end — an endless game of Whac-A-Mole.

Any ruling on partisan gerrymandering will lead to more of the same. The court may decide that it’s unfair to cram as many Democrats as possible into a district, but the politicians in charge of redistricting will always find ways to draw districts to favor their party.

In most states, the people drawing House districts are Republicans. While a few states give control of the redistricting process to independent commissions, most states leave control of redistricting up to their legislatures. The GOP currently controls the entire state government in 24 states and both houses of the legislature in 32. This matters because Republicans’ ability to skew the congressional maps in a handful of states can affect which party controls the U.S. Congress. And as John Ossoff’s loss in the Georgia special election shows, it is incredibly difficult for even the most popular Democratic challengers to overcome districts that were drawn to favor conservatives.

The Republican advantage in the states and in the House of Representatives is the result of the party’s long-term strategy to win seats in state houses around the country. Between 2008 and 2010, Republicans won control of most state legislatures, giving Republicans almost unchecked control over the redistricting process in 2011, which allowed GOP lawmakers to draw maps that gave their party disproportionately more seats in the House of Representatives than the share of votes their candidates received.

That advantage persists, allowing Republicans to control the House even in years when Democrats won the White House and the Senate. In fact, in 2012 there were significantly more votes cast for Democratic congressional candidates than Republican ones, yet Democrats won only 46 percent of the seats in the House.

Democrats are right to celebrate the court’s decision to hear Gill v. Whitford. A Supreme Court ruling that partisan gerrymandering is unconstitutional would certainly be a crucial step toward establishing fairer congressional maps. But even the most stringent standard would not stop politicians from doing everything they can to give members of their own party the upper hand. No court case could ever stop that unless politicians are taken out of the process.

No matter what the court rules, the party that controls the most state legislatures can then control Congress. If Democrats ever hope to control the national agenda, they must take winning state legislatures far more seriously.

Sherrie Preische, Ph.D., is co-owner of the political consulting firm FiftyOne Percent.