WASHINGTON — The Trump administration asked the Supreme Court on Monday to clear the way for an executive order by President Donald Trump that restricts voting by mail, setting up a legal showdown as the president pushes for more control over voting before the midterm elections in November.

The administration filed the emergency application to the justices after a federal appeals court blocked key parts of his executive order Saturday.

In the application, Solicitor General D. John Sauer called the lower court ruling “indefensible,” asserting that it imposed “serious irreparable harm on the federal government” and would bar federal agencies from implementing an executive order “promoting election integrity in the upcoming federal elections in November.”

The legal battle stems from an executive order signed by Trump in late March that had attempted to place limits on mail-in voting, including using federal oversight of the U.S. Postal Service to gain greater control over mail-in voting practices.

The executive order directed the Department of Homeland Security to create state-by-state citizen lists that would help determine voter eligibility. It then called on the Postal Service to use lists provided by states to determine if voters should be allowed to vote by mail.

More than 20 Democratic attorneys general challenged the order in court, arguing that it violated several provisions of the Constitution, including the separation of powers, by having the executive branch take control of functions usually regulated by Congress and the states.

The Supreme Court asked the challengers Monday to respond to the government’s emergency application by next Monday, Aug. 3.

Trump has repeatedly criticized mail-in voting and sought restrictions on it. For years, he has made unfounded claims sowing doubt about voting by mail and claiming that it allows widespread fraud.

So far, federal courts have stymied many of Trump’s efforts to restrict mail voting.

In late June, a federal judge issued a ruling that blocked key parts of the executive order. Judge Indira Talwani, a federal district judge in Massachusetts, concluded that “the Constitution does not grant the President any specific powers over elections.”

She underlined the words “does not.”

This weekend, a three-judge panel from the U.S. Court of Appeals for the 1st Circuit upheld her decision.

The judges wrote that if the president’s order were allowed to go into effect for the midterm elections in November, “it would sow confusion and threaten disenfranchisement of many eligible voters.”

The Constitution gives the states and Congress powers over elections, and it does not give those powers to the president, the judges wrote.

The Supreme Court has shown skepticism of Trump’s efforts to restrict mail-in voting. In late June, the justices upheld a Mississippi law that allows mail-in ballots postmarked by Election Day to be counted if they are received up to five business days later, a rejection of the Trump administration’s efforts to overturn the statute.

In that ruling, Chief Justice John Roberts and Justice Amy Coney Barrett joined the court’s three liberals, announcing that nothing in federal law requires ballots to be received by Election Day provided they are cast by that day.