The Left/Democratic party has had Bernie-esque populist "insurgent" movements intra-party before 2016, look no further than Obama in '08, at Howard Dean's campaign in 04, Bill Bradley in '00, even all the way back to Jerry Brown in 1992 against Bill Clinton. Bernie's moment isn't new per say, at its core, but he can and arguably has changed the game a bit, because his iteration of the idealogical liberal moment has come further than the previous versions.
Slate very eloquently sums up Bernie from a more political science-y perspective that i think captures his candidacy very well.
Also, there is no defending Trump at this point, sorry. I really question why, and how, somebody could turn a blind eye to all his gaffes, his racist rhetoric, and all the other smoke and mirrors bullshit of his masquerading as a political campaign. If you support him in earnest you should be forced to defend all his other policy positions, statements, gaffes, blunders, etc., not cherry pick the ones you think are a major issue right now. (BTW Illegal immigration isn't one of them, sorry, # of illegal immigrants is the lowest it's been in well over a decade, you can google it - because we know the Donald hasn't.)
A really cool way to afford our social programs is to not waste a few Trillion by invading other countries like Iraq, Afghanistan, etc. for oil & hegemony because Dubya had an old score to settle for poppy + VP Cheney was a CEO of a company that made 40 billion in contracts off of Iraq. Raising taxes on people that are 250,000-400,000+ a year, to a more fair level, would not only help alleviate surging income inequality domestically but it would also generate hundreds of billions in tax revenue that the states can use for infrastructure, social programs, etc., that help alleviate poverty and eventually government dependance. Socio-econ 101 folks, it's not hard.
