Article I, Section 9, Clause 8

[identity profile] gridlore.livejournal.com 2004-01-28 05:05 am (UTC)(link)
No Title of Nobility shall be granted by the United States: And no Person holding any Office of Profit or Trust under them, shall, without the Consent of the Congress, accept of any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince, or foreign State.

Theoretically, the Queen could make Bill Gates a Duke, but it would require an act of Congress to authorize it. Since all she is doing is bestowing an honorary position the Dark Lord of Redmond, it doesn't violate the Constitution.

Just a Historical note.. General of the Army Dwight Eisenhower was made a KBE at the end of WWII. Later of course, Dwight Eisenhower, KBE became President.