The Justice Department's mission to enforce the 1957 Civil Rights Act "remains urgent because we do not yet have equal justice," said Garland, whose confirmation hearing is scheduled to begin Monday.
"It would've been better if this conversation had never happened, but the fact remains that it was a conversation between two friends," he said.
Transparency in the hearing’s process would have minimized bias and enabled the public to decide for itself.
Breaking the Silence slammed the letter, calling it a "desperate attempt" of a "discredited far-Right settler organization [Ad Kan] to revive a failed political campaign."
Mueller, a former FBI director, had been examining since 2017 whether Trump's campaign conspired with Moscow to try to influence the election.