The Supreme Court declined Monday to take up a legal dispute targeting the inscription of “In God We Trust” on coins and currency from the Department of Treasury.

Michael Newdow, an activist who filed the case on behalf of a group of atheists, argued Congress's mandate to inscribe the nation’s motto on U.S. money was a violation of the First Amendment’s Establishment Clause, which prohibits Congress from establishing a national religion.

The phrase “In God We Trust” first appeared on coins in 1864, and Congress passed legislation in 1955 requiring all paper and coin currency to bear the words.

But Newdow argued that “by mandating the inscription of facially religious text on every coin and currency bill,” the federal government has turned atheists into “political outsiders’ on the basis of their fundamental religious tenant.”

Newdow suffered a string of defeats in the lower courts, with the 8th U.S. Circuit Court of Appeals agreeing to dismiss the case in 2018.

Newdow has mounted several challenges to what he claims is the government’s unconstitutional endorsement of religion. In 2004, he brought a case arguing the words “under God” in the Pledge of Allegiance violated the First Amendment, though was unsuccessful before the Supreme Court.

He also sought to block Chief Justice John Roberts from saying the phrase “So help me God” while administering the presidential oath of office to President Barack Obama during his inauguration in 2009. Newdow also sought to stop the phrase from being recited in the 2013 and 2017 inaugurations.

A federal court threw out that lawsuit, and the Supreme Court in 2011 declined to take up the case.