Not long ago, liberals were the first to object when they saw the Intelligence Community participating in domestic spying or the FBI lying to judges in order to spy on friends and close colleagues of political candidates. In 1975, the Church Committee (named after Idaho Democratic Sen. Frank Church) excoriated the CIA for, among other things, domestic spying on civilians. Another issue that arose was the use of blackmail and other illegal conduct by the FBI toward Martin Luther King Jr., among others.
This sort of rogue activity by law enforcement and intelligence does not become meaningless just because it is happening to someone liberals hate. Indeed, the idea of law enforcement and intelligence officials taking political sides in an election is an extremely grave one, far more threatening to the values of a free society than anything Trump ever did or attempted in office.
A thorough investigation and explanation will be required to preserve the nation’s republican values against an entrenched and (by design) highly secretive segment of the federal bureaucracy.