Another day, another resignation, another hidden message in a letter.

Daniel Kammen, an energy professor at the University of California, Berkeley, resigned Wednesday from his position as the State Department's science envoy.

Kammen, who was appointed to the position back in February 2016 and has served in many federal roles for more than 20 years, said his decision was tied to President Trump's "attacks on core values of the United States."

"Your failure to condemn white supremacists and neo-Nazis has domestic and international ramifications," he said. "Particularly troubling to me is how your response to Charlottesville is consistent with a broader pattern of behavior that enables sexism and racism, and disregards the welfare of all Americans, the global community and the planet."

Kammen's letter also had a not-so-subtle message: the first letter of each paragraph spelled out the word "IMPEACH." It was akin to another resignation letter sent last week; members of the President's Committee on Arts and the Humanities resigned en masse, and the first letter of each paragraph of their resignation letter spelled out the word "RESIST."

Kammen's resignation is only the latest in the fallout over President Trump's response to the violent clashes in Charlottesville, Va. The president said left-wing protesters were as much to blame for the violence as white supremacists and white nationalists.