+7
Yes, Robert Mueller was a registered Republican. A longtime member of the party, he was appointed as FBI Director by President George W. Bush in 2001 and served in high-ranking Department of Justice roles under both Republican and Democratic administrations, cultivating an reputation for being apolitical.
Wikipedia
Wikipedia
+4
Key details regarding Mueller's political affiliation:
Registered Republican: Throughout his career, including his time as Special Counsel, Mueller was registered as a Republican.
Appointed by Republicans: He was nominated to lead the FBI by George W. Bush.
Reputation: He was often described as a "straight-shooter" or a "by-the-book" prosecutor, and sometimes referred to as a "liberal Republican" or an old-school establishment Republican.
Bipartisan Service: Despite his party affiliation, he was asked to continue as FBI Director for two extra years by President Barack Obama, a Democrat.
Wikipedia
Wikipedia
+5
During his time as Special Counsel investigating Russian interference in the 2016 election, he was frequently criticized by Republican President Donald Trump, who accused him of having conflicts of interest, despite Mueller's Republican background.