So far as I can tell, that act would not be a sexual offense within the meaning of Maryland law.
However, it would certainly be an unwanted touching, a battery. In Maryland, the term “assault,” applies to a completed act of battery (see, e.g., Lamb v. State, 613 A. 2d 402 (Md Ct Spec App 1992.
During the Clinton administration and questions about the possibility of a Clinton criminal charge, the White House Office of Legal Counsel opined that the President, and only the President, is immune from from criminal process during his term because he embodies the entire executive branch. That is, a city police officer cannot take the President into custody and thus paralyze the entire executive branch. Interestingly, this position echoed a virtually identical one taken by the Nixon White House’s Office of Legal Counsel.
No court has ever considered the specific question; Clinton reached a deal with Robert Ray in which he surrendered his law license for five years in exchange for a promise of non-prosecution, and that was after he left office in any event.
Clinton v Jones settled the issue of whether the President could be compelled to civil litigation. (Short answer: yes).
That’s actually a different question entirely: a President who assaults another in a social setting is acting on his own behalf. A President who orders a soldier to act is presumably acting in his capacity as President. The President has immunity from civil liability for acts committed as President. And in general, there seems to be agreement that while the United States has authority to prosecute federal crimes committed by the President, the necessary first step would be impeachment and removal from office – although again no court has confronted the question, but OLC opinions from both Democratic and Republican administrations have asserted this position.
So while a special prosecutor could investigate this, an indictment seems to require impeachment.
Same answer.
Nothing in the written law limits the reach of a grand jury to indict, but again, legal authorities seem to weigh on the side of the necessity of the President being impeached first.