The court’s four liberal justices dissented, saying they would have prohibited construction while a court challenge continues, after a federal appeals court ruled in June that the administration had illegally sidestepped Congress in transferring the Defense Department funds.
“The Court’s decision to let construction continue nevertheless I fear, may operate, in effect, as a final judgment,” Justice Stephen Breyer wrote in a brief dissent for the four liberals.
Friday’s order means the court is not likely even to consider the substance of the issue until after the November election, while work on the wall continues.
Last summer, at an earlier stage in the case, the justices also split 5-4 to allow the administration to begin construction using $2.5 billion in Defense Department funds.
That allowed President Donald Trump to make progress on a major 2016 campaign promise heading into his race for a second term.
The administration wanted to use the money to replace a total of 129 miles (208 kilometers) of rundown or outdated fencing in New Mexico, Arizona and California.
As of mid-July, 92 miles (148 kilometers) have been completed according to U.S. Customs and Border Protection.
The case has its origins in the 35-day partial government shutdown that started in December of 2018. Trump ended the shutdown after Congress gave him approximately $1.4 billion in border wall funding, but that was far less than the $5.7 billion he was seeking.
Trump then declared a national emergency to take cash from other government accounts to use to construct sections of wall.
At the time, the money Trump identified included $2.5 billion in Defense Department money, $3.6 billion from military construction funds and $600 million from the Treasury Department’s asset forfeiture fund.
Adapted from reporting by the Associated Press.