Americans behind on their rent payments may have cheered when the Centers for Disease Control and Prevention announced Tuesday a new eviction moratorium for most of the nation, this one set to last until October. With some 6 million people owing back rent, many of them victims of covid-19’s sudden economic damage, there is little doubt about the need for aid, particularly because people are about to be thrown out of their homes just as disease rates are climbing.

But the CDC’s action was almost certainly illegal. Under pressure from House Speaker Nancy Pelosi (D-Calif.) and progressive Democrats, President Biden and the CDC may have muted accusations that they failed to stick up for desperate renters. The administration also may succeed in giving many Americans a short reprieve from eviction. But perhaps not as long as advertised — because courts may strike it down before October — and at the expense of the rule of law.

The CDC crafted its new moratorium after a previous eviction ban expired last week. The old policy covered the whole country and had been in place since September. But Supreme Court Justice Brett M. Kavanaugh warned in June that the CDC had “exceeded its existing statutory authority by issuing a nationwide eviction moratorium” and that it could not be renewed absent “clear and specific congressional authorization.” Justice Kavanaugh was the crucial fifth vote that stopped the court from immediately striking down the old eviction ban, giving states an extra few weeks to begin distributing some $47 billion in federal rental aid.

As of June, over 6 million people were behind on rent. Landlords across the United States are still owed about $27.5 billion. (Monica Rodman, Sarah Hashemi/The Washington Post)

The CDC on Tuesday tried to get around this ruling by issuing a new ban that covers only areas “experiencing substantial and high levels of community transmission.” This amounts to 80 percent of counties. Advocates argue that the rise of the delta variant may have changed the court’s thinking and that the new policy is more closely tailored to the worsening public health situation. They also argue that Justice Kavanaugh may uphold another temporary policy while federal rental aid money is still only trickling out.

That is unlikely. The law the CDC relies on to justify its unilateral eviction ban authorizes the agency to impose measures such as “inspection, fumigation, disinfection, sanitation, pest extermination, and destruction of animals,” not to freeze the rental housing market month after month in nearly the entire country. Many landlords are themselves desperate, on the hook to keep up their properties, pay taxes and service loans whether their tenants pay their rent. Justice Kavanaugh in June clearly signaled willingness to disregard their plight — and the law’s limitations — for another few weeks, not months.

It is not the Biden administration’s fault that states have been slow to get federal rental aid to needy Americans. But the administration’s only reasonable options were to push states to get their acts together and to request that Congress give the CDC the authority it needed to reimpose an eviction ban. Indeed, the onus remains on states and localities; they cannot count on the new moratorium, issued on shaky legal ground, to absolve them of responsibility to aid renters.

If the Trump administration had ignored a direct warning from the Supreme Court, Democrats would rightfully line up to condemn the president. Mr. Biden does not get a pass on the rule of law because his heart is in the right place.