Here are BO's candidate nomination papers for
Arizona: "I am a natural born citizen of the United States, am at least thirty-five years of age, and have been a resident within the United States for at least fourteen years."
New Hampshire: "I ... meet the qualifications of office for which I am a candidate...."
Illinois: "You should also note that Section 10-8 of our Election Code (10 ILCS 5/10-8) states that candidate petitions '***shall be deemed to be valid unless objection thereto is duly made ***'. No objection was made to Senator Obama's qualifications for office during the five business day objection period. Therefore, no further paperwork was submitted on the subject."
Rhode Island: "The undersigned [Barack Obama] hereby declares that he or she is eligible under the laws and Constitution of the United States to serve in the office of President of the United States if elected..." (Funny, but Rhode Island's form has check boxes only for the Democratic and Republican parties; no third party options are offered.)