Okay, so, both the RNC and DNC are private organizations, so the president doesn't have any say over their nominating processes. As for NATO, the last I heard was that Sanders wanted Russia to join NATO.
There's similarities between all of the current presidential candidates, but that doesn't change the fact that Annoying Orange and Sanders have completely different positions.
When did I say anything about the president having a say over their nominating process? I simply said that they both think the current establishment system is rigged. As for NATO, Sanders has said this "It is not the time to continue wasting tens of billions of dollars helping to defend Europe, let alone assuming more than our share of any cost associated with expanding NATO." And some people look for only specific policies "gun control" could be a major game changer with even many that identify with the left.
But your right both share a similar view that they could use Russia to their advantage..
On a side note: I'm happy with the great amount of people showing up to actually vote this year. Typically most Americans don't vote so it's good.