Trump Says He Has ‘Complete Power’ to Pardon

USconstitutiondotorg

With the exception of impeachment, he can.

Finally, there is no review of pardons. This issue, too, was brought up in the Constitutional Convention, that pardons be granted with the consent of the Senate, but the measure was defeated on the vote of eight states to one. In modern days, there is an office in the Justice Department where pardons are sent, and a Pardons Attorney who reviews and recommends applications. The President may still receive pardons personally, and may grant them at any time. The President need not provide a reason for a pardon, and the courts and the Congress have no legal authority to approve, disapprove, reject, or accept a pardon. Currently, the only way to change the pardon power is by constitutional amendment, though history has shown that the scope of the power can be modified by the courts (as in the acceptance doctrine).

He isn't too far off the mark, but there is a notable exception, impeachment.