Does the President of the USA execute prosecutorial discretion? Is it legal for the President of the USA to direct an official of the DOJ (say, the Director of the FBI) to drop an investigation, as an exercise of prosecutorial discretion? This is the case being made by Andrew McCarthy: [T]he president absolutely has the authority to exercise prosecutorial discretion. A legitimate exercise of executive power cannot be corrupt. A president does not corruptly impede an investigation by deciding that the equities weigh in favor of halting it. That is a decision the president gets to make. Source Clearly, there is some special pleading going on there. But I am wondering whether Mr. McCarthy is correct on a point of law.
Mr. Comey answered this in his testimony. LANKFORD: Okay. Fair enough. If the president wanted to stop an investigation, how would he do that? Knowing it is an ongoing criminal investigation or counterintelligence investigation, would that be a matter of going to you, you perceive, and say, you make it stop because he doesn't have the authority to stop it? How would the president make an ongoing investigation stop? COMEY: I'm not a legal scholar, but as a legal matter, the president is the head of the executive branch and could direct, in theory, we have important norms against this, but could anyone be investigative or not. I think he has the legal authority. All of us ultimately report in the executive branch to the president. LANKFORD: Would that be to you, or the attorney general or who? COMEY: I suppose he could if he wanted to issue a direct order could do it anyway. Through the attorney general or issue it directly to me. This issue also came up in United States v Texas. The obligation to refrain from interference with the FBI is a norm, not a legal requirement. And, like many executive powers, an act that is sometimes legally permitted can become illegal given an improper motive. It is also possible for Congress to find legal acts to be untenably corrupt.
The consequences for the US are perhaps better addressed at Politics; if you're really interested in those consequences, you can re-post this question there. For the police officer shooting a diplomat, the officer may be charged under state law, whatever is normal for an incident of this type; it doesn't matter whether the person is a US citizen or a diplomat or any other kind of alien, regardless of immigration status or lack thereof. If the person is a diplomat, however, the officer is also liable to be prosecuted under federal law, namely 18 USC 1116, which makes it a crime to kill, among others, a "foreign official"; the definition of that term includes any person of a foreign nationality who is duly notified to the United States as an officer or employee of a foreign government or international organization, and who is in the United States on official business, and any member of his family whose presence in the United States is in connection with the presence of such officer or employee. The characterization of the response "just been revoked" as "clearly legal" is inaccurate; a police officer has no power to revoke diplomatic immunity. In fact, only the diplomat's own country can waive this immunity. The United States cannot do so; it can only expel the diplomat.
From Clinton v. Jones 520 U.S. 681 (1997): Deferral of this litigation until petitioner's Presidency ends is not constitutionally required. [...] The separation-of-powers doctrine does not require federal courts to stay all private actions against the President until he leaves office. [...] Nixon v Fitzgerald provides no support for an immunity for unofficial conduct. Regarding official acts, the President is immune. Nixon v. Fitzgerald 457 U.S. 731 (1982): Petitioner, as a former President of the United States, is entitled to absolute immunity from damages liability predicated on his official acts. [...] The President's absolute immunity extends to all acts within the &quot;outer perimeter&quot; of his duties of office.
I think we're talking about In re Hennen, which dealt with the removal of the clerk of the district court in Louisiana: It all these departments power is given to the secretary, to appoint all necessary clerks; 1 Story, 48; and although no power to remove is expressly given, yet there can be no doubt, that these clerks hold their office at the will and discretion of the head of the department. It would be a most extraordinary construction of the law, that all these offices were to be held during life, which must inevitably follow, unless the incumbent was removable at the discretion of the head of the department: the President has certainly no power to remove. These clerks fall under that class of inferior officers, the appointment of which the Constitution authorizes Congress to vest in the head of the department. The same rule, as to the power of removal, must be applied to offices where the appointment is vested in the President alone. The nature of the power, and the control over the officer appointed, does not at all depend on the source from which it emanates. The execution of the power depends upon the authority of law, and not upon the agent who is to administer it. And the Constitution has authorized Congress, in certain cases, to vest this power in the President alone, in the Courts of law, or in the heads of departments; and all inferior officers appointed under each, by authority of law, must hold their office at the discretion of the appointing power. Such is the settled usage and practical construction of the Constitution and laws, under which these offices are held. In re Hennen, 38 U.S. 230, 259–60, 10 L. Ed. 138 (1839) (emphasis added).
As far as I know, every jurisdiction in America limits perjury to cases of lying under oath. Because it seems unlikely that the driver would be under oath at this point, you would probably lack probable cause to make an arrest. At the same time, many states have separate laws addressing the making of false reports, lying to an officer, etc. I'd imagine most jurisdictions would have a law supporting an arrest for lying at the scene, even if not for perjury.
Treason is basically the only crime explicitly defined by the Constitution. According to Article III, Section 3: Treason against the United States, shall consist only in levying war against them, or in adhering to their enemies, giving them aid and comfort. So, no. What this hypothetical president is calling for is unconstitutional, is almost certainly grounds for impeachment, and may even be criminal, but treason it ain't. And that's assuming he actually does it. Simply calling for it, without acting (or directing others to act) to bring it about, may well be protected by the First Amendment.
No The police and the office of the public prosecutor have discretion in which cases they investigate or prosecute. The court may refer an instance of criminality to them but they are under no obligation to do anything with that referral.
The show ignored the existing legal framework. Almost all U.S. police officers are employed by state and local governments and do not report directly to the President, even in an emergency. A small number of law enforcement officers are federal employees with a direct line of command to the President (e.g. the Secret Service and the security guards in the General Services Administration and TSA officers), but a law enforcement officer, unlike a member of the military or a CIA officer, does not simply follow the orders of the civilians to whom his superiors are responsible without the intervention of their law enforcement superiors based solely upon that civilian's whims and directions the way that a soldier would. The Secret Service has some limited authority to direct and even deputize local law enforcement officers in pursuit of their missions, but that would probably not extend to the kind of national security kill order contemplated in this episode. This said, lots of law enforcement officers are ex-military, most law enforcement agencies has a quasi-military organizational structure, and in the extreme circumstances of Designated Survivor, it wouldn't be shocking for law enforcement officers to follow their natural military chain of command intuitions rather than the law that actually applies in these situations. Law enforcement officers are personality types that are very deferential to authority which is a natural counterpart to support for their hierarchical view of the world that endows them with their own authority. There is no one in the loop to play devil's advocate for the suspected terrorist. But, strictly speaking, the proper protocol within the U.S. would be to have a CIA agent make the strike (because the military is prevented by the posse comitatus act from doing so, unless these events counted as an "insurrection" which they very well might in which case the military could be involved), rather than a law enforcement officer. Incidentally, the U.S. Supreme Court has basically held that the citizenship of the suspected terrorist is irrelevant, even though policy makers in all of the Presidential administrations since 9-11 have not been very comfortable with that state of the law and have sought to distinguish U.S. citizens from non-U.S. citizens in their own policies.