Mick

Yes, the Nixon case set the precedent. But I don't think the Constitution is worded that way.

The limitation is that a pardon cannot be issued for a crime that has not yet been committed and the test is, has President Trump committed a crime?

As we know, the US Government is split in to three entities: Legislative (Congress), Executive branch (President) and Judicial (Supreme Court). They all check and balance each other. But the Presidential power of Pardon only applies to the Executive Branch. When a President issues a legitimate pardon it is, legally irrefutable.

So the question that would be tested if Trump attempted to Pardon himself, does the President hold so much power that he is above the law?

The Constitution would answer this as 'no'.

The United States is a Republic and they made it so that nobody is above the law, not even the President. It's not like here in the UK, where our Head of State, is above the law, her majesty, The Queen.

There have been historical attempts in Congress to limit the scope of the Presidential pardon, but every time they have failed because the power is granted in the Constitution, it's in the original document.

That said, Congress does hold one minor balance of the pardon power, this is in cases where Congress has called a witness and they have refused to give evidence, they would be in Contempt of Congress and a President does not have the privilege of pardoning in cases of contempt, the crime being pardoned has to be at federal level.

I am sure Nixon himself, was going through the motions, could he pardon himself or not?

History records he tried to hang on to his Presidency so desperately, but his political support was completely eroded and impeachment was inevitable. He sure was nudged before he was pushed.

When President Ford pardoned Nixon, in 1974, there is no evidence of a special deal being done. Ford/Nixon denied any deal was done. But I am sure there could have been a little, gentlemen agreement, where Nixon says, if I resign, the desk, the curtains, the oval office, the whole house is yours, but first I ask that you 'Pardon' me once I leave office.