President Donald Trump's attorney, Rudy Giuliani, says the president can pardon himself of crimes.

The Presidential pardon power comes from Artilce II, Section 2, of the United States Constitution. It states:

"The President ... shall have Power to grant Reprieves and Pardons for Offenses against the United States, except in Cases of Impeachment."

There are only two exceptions stated for the power.

First, the power to pardon only applies to offenses against the United States. That means state crimes cannot be pardoned.

Second, the pardon power does not apply to impeachment.

Beyond what is stated in the constitution there is no legal authority. The issue has never been tested in the courts.

In 1974, President Nixon and his lawyers also considered whether he could self pardon. An August 5, 1974, Department of Justice memo by Mary Lawton, the Acting Assistant Attorney General, concluded a president could not pardon himself.

The conclusion was no. But the analysis was unbelievable short. The sum total of the analysis by Ms. Lawston stated:

"Under the fundamental rule that no one may be a judge in his own case, it would seem that the question should be answered in the negative."

No legal citations were made.

In Williams v. Pennsylvania, a 2016 United States Supreme Court case, there was a murder conviction. The defendant appealed arguing the district attorney's office had obtained false evidence and hid exculpatory evidence. The evidence involved the victim having sexually abused the defendant. Finding a violation there was a stay of execution and new sentencing was ordered. The issue then went to the Pennsylvania Supreme Court. There, the Pennsylvania Supreme Court vacated the stay and reinstated the death penalty.

The problem?

By the time the case made it to the Pennsylvania Supreme Court the district attorney in the original murder trial had been appointed the Chief Justice. The result was the chief judge was essentially ruling on the validity of his own actions when he was district attorney.

The US Supreme Court tossed the decision by the Pennsylvania Supreme Court, ruling it is constitutionally impermissible to have the same person be both the accuser and the judge. The United States Supreme Court found a due process violation. The court said there was bias because:

"This objective risk of bias is reflected in the due process maxim that no man can be a judge in his own case and no man is permitted to try cases where he has an interest in the outcome."

In 2009 the US Supreme Court in Caperton v. A. T. Massey Coal Co. made a similar ruling in a case out of a John Grisham novel. There, a company found liable for $50 million in damages poured millions into electing a friendly judge to the West Virginia court of appeal. Once seated, the judge reversed the verdict. The Supreme Court said this was a due process violation.

"No man can be a judge in his own case"

In these situations there was unfairness to X caused from bias by Y where Y was being his own judge.

The court said Y's actions violated the Due Process Clause of the Fourteenth Amendment.

An untested question is, does the Due Process clause create a restriction on the President's pardon power under Article II, Section 2?

Could President Trump pardon himself from failing to pay taxes?

Or, using an even more outrageous example provided by Rudy Giuliani, what if President Trump shot someone. Assume the president killed the vice-president in the white house. Could the president pardon himself of the federal crime of murder?

In our view the result is so repugnant the Supreme Court would find the maxim applies, even without the 14th Amendment as a basic, unstated principle of American democracy. That is what differentiates our democractic republic from the English monarchy our founders abhored.

It is reasonable to conclude the concept of a self-pardon was so ridiculous the founders never considered the issue. If they had, no reasonable person would have concluded that was right or proper.

The Supreme Court may seem politically based on the ideological leanings of the majority of justices. The court may say it is there to make unpopular rulings unfettered by public opinion. But the fact is the court does make decisions based on public opinion. Does anyone think a ruling for gay marriage in the 21st century would have happened in the 18th century? Of course not. The issue was simply unthinkable at the time.

Similarly, the issue of a presidential self pardon was unthinkable to the founders, and still unacceptable today.

We do not imagine the United States Supreme Court would rule the President could commit murder and pardon himself from any criminal liability.

Implied in a "pardon" is an act towards someone else. That the president has evaluated the situation involving Y and given them a reprieve or pardon. It simply does not apply to the president.