WASHINGTON — The Supreme Court weighed in on behalf of Arizona's Republican leaders Saturday and cleared the way for them to enforce a new state law that makes it a felony for anyone other than family members and caregivers to deliver mail-in ballots to official polling places.

The high court in a brief order with no registered dissents blocked a ruling of the U.S. 9th Circuit Court of Appeals, which on Friday had halted enforcement of the law.

It is not clear what will happen now. County election officials had said they did not plan to vigorously enforce the law. However, the Arizona Republican Party said it was training volunteers to watch and report people seen dropping off ballots.

In April, shortly after the restriction was adopted on a party-line vote in the state Legislature, lawyers for the Democratic National Committee sued, arguing the restriction could prevent thousands of legal voters from having their ballots counted.

The law makes a crime out of the “long-standing practice pursuant to which thousands of voters have relied on friends, neighbors, advocacy and political organizations and campaigns to collect and deliver their early ballots to ensure they arrive by 7 p.m Election Day deadline,” they said.

Arizona lawmakers passed the restriction in March. Republicans said that allowing community groups to collect and deliver mail-in ballots could result in fraud.

A federal judge refused to block the new law, and a 9th Circuit panel upheld that decision on a 2-1 vote.

But Friday, the full 9th Circuit reconsidered that decision and voted to put the Arizona law on hold.

Its order came on a 6-5 vote, with Democratic appointees making the majority and five Republican appointees in dissent. Chief Judge Sidney Thomas, speaking for the majority, said the order would maintain the status quo and prevent confusion.

But on Friday evening, Arizona's attorney general and the Arizona Republican Party filed a joint emergency appeal with Supreme Court Justice Anthony Kennedy. They asked for a stay of the appeals court's decision and argued the last-minute order from the 9th Circuit was disruptive.

“The application for stay presented to Justice Kennedy and by him referred to the Court is granted,” the court said in a Saturday order.

The handling of the matter suggests the justice agreed with Arizona's claim that the federal courts should not interfere on the eve of the election.

david.savage@latimes.com