@SavoirFaire – Absolute? Maybe, but maybe not.
All the precedents you cite are correct. But as we’ve all learned, we have someone in the White House whose words & actions become more unprecedented every day. That could apply to his power to pardon as well.
The issue of bribery in exchange for an executive pardon is an example. It’s a charge that up to now has never been made and proven against a president. But things change. The federal anti-bribery statute, 18 USC Sec. 201 makes it a crime for any public official to demand or receive anything of value in exchange for performing an official act, or not carrying out a public duty. The scope of the law is broad, with few exceptions.
How would this apply in the case of a presidential pardon given in exchange for false testimony by a witness, or paid for with a campaign contribution? We may find out soon. On Dec. 1 2020 Washington DC District Court Judge Beryl Howell unsealed an order granting the Justice Department permission to gather evidence in an investigation of “lobbying to secure a presidential pardon or reprieve of sentence in exchange for a substantial campaign contibution.”
Time will tell…