 The candidates sparred at a debate at the Ronald Reagan Presidential Library in Simi Valley, California, on January 30, with former First Lady Nancy Reagan present in the front row.The most heated exchange came as Romney accused McCain of dirty tricks in his misleading Florida statements about Romney having proposed an Iraq withdrawal timetable.On January 31, McCain received the important endorsement of Governor of California Arnold Schwarzenegger and began campaigning with him; Schwarzenegger had previously refrained from endorsing either McCain or Giuliani because he counted both men as friends.