The Limits of Power

With Donald Trump's pardon of Joe Arpaio for a federal contempt of court conviction, Trump is threatening to destroy the power of the judicial branch of government. He seems to think that his power to pardon is absolute:

In his Saturday morning tweets, the President referenced the fact that he holds presidential pardoning powers, saying, "While all agree the U. S. President has the complete power to pardon, why think of that when only crime so far is LEAKS against us. FAKE NEWS."

Sorry to break it to Donnie, but he ain't all powerful. Realistically, he can't pardon himself. And he can't pardon someone in exchange for a bribe -- that in itself would be a crime.

And, more to the point, he can't pardon anyone for crimes charged under state law:

The Constitution gives the president “power to grant reprieves and pardons for offenses against the United States, except in cases of impeachment.”  

Since Trump has never actually read the Constitution, he doesn't seem to realize that. But Robert Mueller does:

Special counsel Robert Mueller’s team is working with New York Attorney General Eric Schneiderman on its investigation into Paul Manafort and his financial transactions, according to several people familiar with the matter.

The cooperation is the latest indication that the federal probe into President Donald Trump’s former campaign chairman is intensifying. It also could potentially provide Mueller with additional leverage to get Manafort to cooperate in the larger investigation into Trump’s campaign, as Trump does not have pardon power over state crimes.

With all of Trump's questionable financial dealings with Russian oligarchs, Trump himself is likely open to prosecution in New York, New Jersey and Florida for money laundering with his real estate and casino transactions.

And remember, the FBI took down Al Capone for tax fraud. Perhaps Trump's reluctance to release his tax returns is that if all the states where he does business could see the entirety of his financial manipulations they could convict him of tax evasion.