Congress passed and President Obama signed into law the Tobacco Control Act of 2009, which guarantees that cigarettes and other combustible tobacco products will continue to remain legal in the United States–despite Congress’s explicit finding that tobacco products are inherently dangerous and that they are the leading preventable cause of death in the United States.
Was that criminal, given that it will result in hundreds of thousands of needless deaths, or was it a policy decision?
This is an official act undertaken while he is President, one that does not violate clearly established law, and therefore one for which he enjoys absolute immunity even after he leaves office. The date of the case (1982) and the name of the petitioner (Nixon, as in Richard M.) should tell you that this is an immunity that continues after the president leaves office.
EDIT Absolute immunity applies to civil liability, not criminal.
I agree! But under the law as it stands now, Trump will not be held criminally responsible for this decision.