Quote from the dissent:
"It then goes a step further: “In dividing official from unofficial conduct, courts may not inquire into the President’s motives.” Ante, at 18. It is one thing to say that motive is irrelevant to questions regarding the scope of civil liability, but it is quite another to make it irrelevant to questions regarding criminal liability. Under that rule, any use of official power for any purpose, even the most corrupt purpose indicated by objective evidence of the most corrupt motives and intent, remains official and immune. Under the majority’s test, if it can be called a test, the category of Presidential action that can be deemed “unofficial” is destined to be vanishingly small."