Millennials have respect for his straightforward delivery and his sincerity and they tend to be more liberal and effected deeply by some of his message. Sages are proven only by time and integrity.
Could it possibly be that our Hispanic VP heir apparent might stand back a bit to see what happens? This is probably a first of conceptually comparing the two leaders, but they are surely compatible with their lifetimes of being Progressive...no flip flopping...Liberalism. I think Julian Castro could very likely swing the General Election based on his connection with the largest voting bloc in the US. He will also be honest and straightforward about immigration, as his grandmother was one...and the story is heart-warming.
Also a poll came out recently that said for the first time over 50% of Americans consider themselves Liberal. Couldn't find the link, but Populism, concern for the middle and lower classes, is sprouting up in opposition to formerly establishment parties of Southern European elections, so maybe it's 100th Monkey Time?????