If Senate Democrats plan to subpoena conservative judicial activists as part of a Supreme Court ethics investigation, Republicans say they must go after liberal advocates the same way.

Senate Judiciary Committee Chairman Dick Durbin (D-IL) has sought to authorize subpoenas for influential conservative judicial activist Leonard Leo and GOP megadonor Harlan Crow, defending the subpoenas as necessary after the pair's “defensive, dismissive refusals” to cooperate with a congressional investigation. Now, Republicans have proposed more than 150 additional subpoenas to broaden an investigation they say is one-sided against conservative justices on the high court.

The Washington Examiner obtained copies of amendments that Republicans want added to the proposal to subpoena Leo and Crow. Sen. Marsha Blackburn (R-TN) previously brought up one major amendment was by demanding subpoenas for Democratic-appointed Justice Sonia Sotomayor's staff and book publisher.

"What we learned was that over the years, her staff has pressured public institutions to buy her books," Blackburn said before the vote to subpoena Crow and Leo fell apart on Nov. 9, saying Democrats were engaging in an "assault on the legitimacy of the Supreme Court."