If it is not treason (to deny due process and justice to appellants in Federal court and to work at hindering the work of a branch of government) then what do we call it?
I looked up the definition of treason at the Meriam-Webster dictionary:
the crime of trying to overthrow your country's government
and at The US Code (Legal Information Institute)
Whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort
I found out that even Jeffereson Davis, president of the Confederate States during the Civil War, was not convicted of treason.
So, with apologies, I retract my supposition. McConnell is not guilty of treason.