Arizonans live in one of the relatively few states that can recall its elected Federal officials.....There is an effort underway in New Jersey (uphill and stalled for now by the courts) to recall Menendez.....Once McCain starts moving to the left again, he should face recall.
http://www.recallcongressnow.org/
Arizonas admission as a state was held up by President Taft because the proposed constitution had a recall provision in it and it included judges. Recall was an innovation by the progressives, pioneered in California, that Taft didnt like it at all. Arizona removed the offending provision in order to gain statehood but it delayed admission by a month, putting it behind New Mexico. Hence the nickname The Baby State. As soon as statehood was attained the people of Arizona put the recall provision back in.
Arizona was admitted early in 1912. The 17th amendment was not ratified until more than a year later. When the recall was added to the state constitution Arizonans could not even vote for a Senator much less recall them.
Both Senator McCain and Senator Kyl have pledged to voluntarily abide by the result of any recall attempt but they are not obligated to by law.