Bernie Sanders argues that if no candidate reaches the threshold of delegates needed to earn the Democratic nomination, then it should automatically go to the candidate who receives the most delegates.

The Vermont senator is the only candidate of the seven other still in the race that feels this way, and it has further increased tensions between himself and the Democratic National Committee.

'No, no, I think the rules are set and we ought to follow the rules. Especially when someone says follow the rules who's not even a Democrat,' Democratic Congressman Juan Vargas, who endorsed former New York City Mayor Mike Bloomberg, told Politico. 'He just wants us to rubber stamp his election, which we shouldn't do. I certainly won't do.'

Montana Democratic Senator Jon Tester, who has not endorsed a candidate, added that the rules shouldn't be bent for any candidate.

'That's not what the rules say,' Tester lamented. 'Come on, we've been dealing with a president who breaks the rules all the time, let's not drop to that standard.'