How many US presidents have been knighted?

Answer 1

If your question is relating to receiving honorary British knigthoods, then the answer is two; Reagan and Bush, both received the honor after leaving office. The honorary knighthood does include kneeling or the title of Sir.

Members of the US government are forbidden from receiving a title of nobility under the Nobility Clause (Article I, Section 9, Clause 8 of the United States Constitution). In some instances Knighthood may fall in this category. It is unlikely any active politician would want to accept this beyond an honorary gift with no title, as it would be political suicide as well. Though, this law does not prevent former government members from receiving a title of nobility.

This is was an important topic among the framers of the constitution.

EDIT: Actually, Article I, Section 9, Clause 8 states: "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." Note the phrase WITHOUT THE CONSENT OF THE CONGRESS.

President Dwight D. Eisenhower was knighted by the King of Denmark and inducted into the Order of the Elephant (the highest order of knighthood in Denmark) while he was still General of the Army shortly following the victory of the Allies in World War II. General Eisenhower was also inducted into several orders by other allied nations, including Great Britain (Knight Grand Cross of the Most Honorable Order of the Bath, the highest accolade that can be bestowed upon someone not a British citizen). So, as far as I know, President Eisenhower was the only US President to hold knighthood while in office, though he did receive those accolades before becoming President of the United States of America.