During an interview on Monday, McCain said he was confident they would get the 60 votes. However, he said the most difficult hurdle would be the 67 votes needed to override a veto by the president.
Republicans will attempt to pass their resolution of disapproval that prevents the deal from going through. The president would surely veto that resolution and then two-thirds majority of the Senate would be required to overturn his veto.
For the Republicans to override a presidential veto they would need 12 Democrats to vote against the President, said McCain.
The President needs 34 Senators from the Democrats to support the deal to defeat the Republicans resolution of disapproval. Thus far, 18 Democrats have come out in support of the nuclear deal and just one, New York Senator Charles Schumer has publicly opposed it.
The White House along with those against the nuclear deal is going through heavy lobbying. Lawmakers are expected during their current August recess to talk to their constituents to find out their opinions on the Iran deal.
McCain said some of his constituents have already spoken to him expressing their opposition to the nuclear deal.
McCain criticized the President for comparing those opposed to the deal and along with the Republicans to hardliners in Iran who also want the stop the deal.
McCain said he thinks the president has cheapened and demeaned the presidency by making that type of a comment.
The chairman of the Armed Services lamented that the deal with Iran was not discussed that much during the first presidential debate last week.
He said he felt Carly Fiorina made a good impression and that Marco Rubio did well. He also thought Jeb Bush did fairly well.
McCain said that attention on Donald Trump was making it hard to have a more serious examination of the other participants in the debate and issues of national security.