Boris Epshteyn stands to the side of the briefing room as White House press secretary Sean Spicer speaks during the daily news briefing at the White House, in Washington, Tuesday, Feb. 7, 2017. (AP Photo/Carolyn Kaster)
CNN  — 

Boris Epshteyn, a close adviser to Donald Trump and former White House aide, pleaded not guilty on Tuesday to election subversion charges stemming from an April?indictment in Arizona.

Epshteyn, who appeared in court Tuesday via phone, is one of 18 defendants who, according to the indictment, “schemed to prevent the lawful transfer of the presidency to keep Unindicted Coconspirator 1 in office against the will of?Arizona’s voters.”

While Trump is not among those charged in Arizona, the details in the indictment suggest he is “Unindicted Coconspirator 1.”

The scheme, according to the indictment, called for the fake electors to fraudulently vote for Trump, “falsely claiming to be the duly elected and qualified Electors for President and Vice President of the United States from the State of Arizona.”

Epshteyn joined the Trump campaign in 2016 and is considered one of?the former president’s?most loyal?advisers, speaking with?him?regularly. He was alongside Trump during his arraignment in?his New York?hush money case?and traveled with him to arraignments in Georgia and Washington, DC.

Others charged in the indictment include former Trump White House chief of staff Mark Meadows, along with former Trump attorneys Rudy Giuliani, John Eastman and Christina Bobb.?All have pleaded not guilty.