we need a constitutional amendment curtailing the presidential pardon

[Novara]

9. IIRC, the founders debated limits on pardons ...

... but they were sure that no one could ever be this corrupt.

The only limits for pardons have to do with impeachments.

But then again, this extent of criminality and sedition has never been tested before. My hope is that he will be convicted for sedition at least. I think it's a slam dunk but what do I know?

It would seem that this applies (and not only to him):

Fourteenth Amendment Citizenship, Equal Protection, and Other Post-Civil War Provisions

Section 3 Disqualification and Public Debt

No person shall be a Senator or Representative in Congress, or elector of President and Vice-President, or hold any office, civil or military, under the United States, or under any State, who, having previously taken an oath, as a member of Congress, or as an officer of the United States, or as a member of any State legislature, or as an executive or judicial officer of any State, to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof. But Congress may by a vote of two-thirds of each House, remove such disability.

https://constitution.congress.gov/browse/amendment-14/section-3/

Seems pretty obvious to me.