Longtime Democratic strategist Doug Schoen announced Sunday that he will no longer be able to support Hillary Clinton for president.
Schoen had previously worked in the White House for six years as a pollster for former President Bill Clinton.
In an op-ed in the Hill, Schoen said that he believed the United States could face a "constitutional crisis" if Clinton is elected president due to the looming FBI investigation into her private email server and the email practices of her aides.
"I say this because regardless of what Secretary Clinton did or didn't do or what her aide, Huma Abedin, did or didn't do or even what Anthony Weiner did or didn't do, I am now convinced that we will be facing the very real possibility of a constitutional crisis with many dimensions and deleterious consequences should Secretary Clinton win the election," Schoen wrote.
"In the best case scenario, there will be at the very least a criminal investigation of President-elect Clinton," Schoen continued. "And there will be a criminal investigation of Huma Abedin, which is apparently ongoing. Furthermore, there will be potential investigations into the actions of the Justice Department and most of all the FBI and its director, James Comey."
Schoen first made his announcement in a regular appearance on Fox News on Sunday in what took host Harris Faulkner by surprise.
Schoen has also said that he would not support Donald Trump.