The majority has changed it's mind because they are listening to bullshit put out there. They are falling for the fear card, one more time. They are not hearing anything from those wanting to say no as to what should be done if this deal isn't taken. Iran WILL have the bombs in short order without the deal. As with all deals, nothing is impossible. Just because you sign a deal with someone does not mean they will honor that deal in total. In fact, often they will find a way to skirt the deal to their benefit and leave you with a worthless lawsuit. You may win, on paper, but collecting is another matter.