President Donald Trump's personal lawyer, John Dowd, said Monday that the "president cannot obstruct justice because he is the chief law enforcement officer under (the Constitution's Article II) and has every right to express his view of any case."
As stated, that is probably not an accurate statement of the law.
Obstruction of justice is a general term applying to a number of federal crimes. Obstruction crimes usually consist of 1) an act and 2) the requisite criminal intent. The "act" in obstruction is influencing, obstructing or impeding any one of the "pending proceedings" specifically described in several different obstruction statutes.
What qualifies as a "pending proceeding" has been debated over the years. A pending congressional investigation or court case qualifies as a pending proceeding under certain obstruction statutes.
But it's less certain as to whether, if Trump did have knowledge of Michael Flynn's false statements to the FBI, that would fit into the obstruction statutes, if that knowledge occurred prior to any "proceeding."
Even if Trump did interfere with a pending proceeding, this alone is not enough. The interference must be done with "corrupt" intent, which Congress has defined as having an "improper purpose."
In other words, a president can — and does — influence investigations and proceedings. As the head of the executive branch, he is not only expected to do so; he cannot avoid doing so.
The president's views influence, if not direct, Department of Justice policy. This is legal, too, so long as the president does so for the public benefit, and not for an improper purpose, such as self-preservation. The president can absolutely obstruct justice by influencing an investigation or a proceeding, but only if it is with a corrupt purpose.
Reasonable legal minds differ as to whether a sitting president can be prosecuted in state or federal court.
Even if the president cannot be prosecuted while still in office, it is relevant to determine if the president commits obstruction. First, the commission of a "high crime" like obstruction is relevant to whether the president is impeachable. Second, the Constitution explicitly tells us that the president can be impeached, removed and then prosecuted for conduct committed while in office.
If the tweet from Trump's lawyer is intended to suggest the president cannot commit crimes, that is categorically untrue. Not only can the president commit a crime, he can (eventually) be prosecuted for it.
If not, then Gerald Ford would have had no reason to pardon Richard Nixon after the 37th president resigned from office. While Nixon may have believed that what the president does is not illegal, the weight of legal authority suggests otherwise.
Danny Cevallos is an MSNBC legal analyst. Follow him on Twitter @CevallosLaw