Amanda Frost is a law professor at American University.

The Supreme Court will hear arguments Wednesday in a case challenging President Trump’s travel ban that raises major constitutional questions about the scope of presidential power over immigration. Lurking in the background, though, is an equally important question about the federal courts’ authority to check abuses of federal governmental power.

The Trump administration argues that even if the order banning travel is unconstitutional, the lower federal courts had no authority to block it from being implemented nationwide. By the administration’s logic, a court can do no more than protect individual plaintiffs from the government’s unconstitutional policies; those who do not have the capacity to file similar lawsuits are out of luck.

That cannot be right. As Alexander Hamilton explained in the Federalist Papers, federal courts “guard the Constitution and the rights of individuals from . . . dangerous innovations in the government.” Nationwide injunctions are a vital tool to do just that.

Trump’s travel ban illustrates why courts must have the power to issue nationwide injunctions. Just several days into his presidency, Trump issued an order barring nationals of seven predominantly Muslim countries from entering the United States. On its face, the order applied to everyone from those countries — even those with deep ties to the United States, such as green-card holders who lived here for most of their lives with U.S. citizen family members. The clumsily written order created chaos at the nation’s airports and disrupted countless lives.

Lawyers quickly mounted a challenge to the travel ban and within a week won a preliminary nationwide injunction that prevented the government from implementing the order while it was being litigated. Not long after, the administration rescinded the order and replaced it with a narrower version — one that did not apply to green-card holders and exempted others with close ties to the United States from its reach.

Imagine what would have happened if the federal courts had no power to enjoin the executive order nationwide and instead could grant relief only to the individual plaintiffs in the cases before them. The Trump administration — despite losing in court — would have almost certainly continued to block thousands of people covered by the travel ban from entering the United States. Although lawyers could have tried to bring the case as a class action on behalf of all such people, existing rules make it very difficult to certify such a diverse class. As a result, only the handful of noncitizens with the money or connections to hire a lawyer would have been able to vindicate their rights.

Yes, the Supreme Court would eventually have addressed the constitutionality of that first executive order. Unlike lower federal court decisions, Supreme Court rulings create binding precedent that applies nationwide, rendering a nationwide injunction unnecessary. But cases can take months or years to reach the Supreme Court, subjecting thousands to an indefensible policy in the meantime.

Immigration is not the only area in which nationwide injunctions are sometimes essential. The court-ordered remedies for illegal restrictions on voting, discrimination in public education, and unlawful regulations affecting clean air and water should usually apply to everyone similarly situated to the parties bringing the case. Indeed, in some cases it is hard to see how courts could give a meaningful remedy only to the plaintiffs. How do you give an African American plaintiff the right to attend a desegregated school without ordering the school to let in other African American children?

Opponents of nationwide injunctions argue that plaintiffs forum-shop for friendly district court judges whose decisions then stymie perfectly legal federal policies for months or years as cases make their way through the courts. But the government can immediately ask a three-judge appellate court to narrow or reverse a district court’s nationwide injunction, and the Supreme Court can also weigh in quickly on that question. Indeed, the Supreme Court did so in the most recent challenge to Trump’s travel restrictions, lifting the nationwide injunction and allowing the current version of the travel ban to go into effect during the litigation.

Nationwide injunctions are an issue that should unite those on both sides of the political spectrum, because Democrats and Republicans alike have reasons to fear federal overreach. Today, courts in blue states are issuing nationwide injunctions barring the Trump administration’s policies, but just a few years ago courts did the same thing to President Barack Obama. If we want federal courts to serve as a meaningful check on abuse of federal power, they must be able to halt constitutionally questionable policies in appropriate cases — albeit with a speedy path to appellate and Supreme Court review of such injunctions to ensure they are justified.

Our only other choice is to trust that the federal government will voluntarily avoid implementing policies that violate our constitutional rights. But as Alexander Hamilton explained in 1788, we cannot rely on that.

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