One recurring argument in the ongoing debate over partisan gerrymandering suits is that, if they can be brought, they will inundate the federal courts. Wisconsin advanced this floodgates claim in Whitford, asserting that courts would have to engage in “unprecedented intervention in the political process” if the plaintiffs prevailed. Similarly, North Carolina warned in Rucho of an “onslaught of litigation” if partisan gerrymandering actions were deemed justiciable.

At first glance, recent developments seem to show the floodgates opening. Over a span of just ten days in late April and early May, federal courts struck down numerous congressional districts on partisan gerrymandering grounds in Michigan and Ohio. The actual upshot of these decisions, though, is almost exactly the opposite. Now that courts have invalidated congressional districts in Maryland, Michigan, North Carolina, Ohio, and Pennsylvania, there are very few remaining plans that could successfully be challenged. If the Court permitted partisan gerrymandering claims to proceed, the ensuing volume of litigation would thus be more like a trickle than a flood.

Consider the congressional maps that were used in the 2016 and 2018 elections. The single most asymmetric plan in effect in 2016, Pennsylvania’s, was struck down by a state court and replaced by a far more balanced remedial map. Similarly, three of the four most pro-Republican plans in effect in 2018 (Michigan’s, North Carolina’s, and Ohio’s), were invalidated by federal courts, as was one of the two most pro-Democratic maps (Maryland’s). On the pro-Republican side, only South Carolina’s plan is about as biased as the stricken maps but has not yet been attacked. On the pro-Democratic side, only Massachusetts’s plan is highly skewed but has not yet given rise to a lawsuit.

Moreover, under the legal standard that was adopted by the Michigan, North Carolina, and Ohio courts, partisan intent and a large and durable partisan asymmetry are not enough for the plaintiffs to succeed. They must also demonstrate that the challenged map’s bias is greater than expected given the state’s political geography and nonpartisan redistricting objectives. However, computer simulations for South Carolina and Massachusetts show that both states’ plans are about as skewed as thousands of randomly generated maps. It’s therefore unlikely that either plan would be legally vulnerable under the test around which the lower courts have converged.

Accordingly, claims of an “onslaught” of lawsuits, resulting in “unprecedented” judicial intervention, appear hugely overblown. If the Supreme Court leaves the door open for partisan gerrymandering suits, there may actually be no meritorious cases left to file at the congressional level. This is because litigants have already targeted almost all of the egregious plans around the country. It’s also because, under the lower courts’ test, there simply aren’t that many unlawful maps in the first place.