Could convention rule changes cost Trump the nomination?

Aired: 7/10/2016 | 0:04:08 | Clip
Description If the forces opposed to Donald Trump have any hope of derailing the presumptive nominee, it would be through changes in the convention rules—rules that would free delegates from the requirement to vote on the first ballot for the candidate that got them to Cleveland—or rules that would require the nominee to win a 60 percent “supermajority” of delegate votes. Jeff Greenfield reports.