I am not surprised that Obama's were not invited to the wedding. Yes Prince William is 2nd in line for throne. This wedding is state affair and business will be closed for the Wedding. Their are so many other royals will be invited and some are relatives of the British Royal Family.Plus William and Kate wanted close friends and people that are important in their lives. Kate has very big family on both sides.President and First Lady got invite to London in May and will stay at Buckingham Palace which is a huge deal.
President Barack Obama and other world leaders were also left off the attendance list, although British Prime Minister David Cameron and foreign royal families were included. According to The Sunday Times, this is due to William being second in line to the throne, and not the heir.