Nanclus

From Memory Alpha, the free Star Trek reference.

"Mr. President, I don't know what to believe."

Nanclus was ambassador of the Romulan Star Empire to the Federation in 2293.

In the same year, he was part of the Khitomer conspiracy, which tried to sabotage the peace negotiations on Khitomer between the Klingon Empire and the Federation. After the conspiracy was exposed, Nanclus was taken into custody and charged with treason. (Star Trek VI: The Undiscovered Country)

It's unclear whether his conspiracy was sanctioned by the Romulan government, although it would be consistent with its history.

Nanclus was played by Darryl Henriques.