Senator Kennedy ran against sitting President Jimmy Carter and took the fight to the convention for a floor vote.  He was behind Carter in the assumed count 976 delegates. How did he manage to take the vote to the convention?  Because it is the RULZ.  Read about elections in reference texts on how tro run organizations in a fair and just manner.  You'll find the same concepts abide.

As long as the other candidates don't condede. there is no nominee until the convention votes.  Check it out.