Actually, they knocked off 2 seats, both held by Democrats who died in office in 1865 and 1867, respectively: James Moore Wayne, appointed by President Jackson (who occupied the 5th Associate Justice seat) and John Catron (who was the first and only one to occupy the 7th Associate Justice seat), also appointed by the outgoing Jackson in the Spring of 1837 (who was the former TN Chief Justice and Van Buren’s campaign manager here in the state).
we need to knock off a couple of the leftists
You’re right, DJ, Congress eliminated two seats to set the number of justices at 8 (after recently having increased them to 10); it was years later that Congress added a 9th seat to SCOTUS. But my point remains that Congress was not able to remove sitting justices from the Court merely by reducing the number of seats.