Cindy McCain only wants to be a Senator for one single reason. She does not care about being a politician. She does not care about the 'People of Arizona', she does not care about America, or Americans.
The only reason she wants to be a Senator is to be able to swipe at Trump, who she blames for her husband's death. She is psychotic. She wants 'revenge', just like her husband before her.
The Union, The Consititution, The people of Arizona, and what would be best for them, are at the very last of the list in her mind.