In looking forward to the final years of a viable Republican party, after the failure of the would-be re-aligner Trump to transform a hated globalist elitist party into a populist nationalist party, we can clearly see the Bernie style candidates sweeping into office in order to do populism for real, and likely doing a lot on the anti-globalist front as well (at least, getting out of de-industrializing trade deals, and winding down so much of our fruitless global military occupation).*
But would this mean a rehabilitation of the Democrats as a party, or perhaps the birth of a new major party that displaces one of the old ones? Bernie has been an Independent, albeit one who caucuses with the Dems, and whose initial core of voters would be more sympathetic to the Dems than the GOP.
Two major changes coming up suggest it might actually become a new major party that displaces one of the existing major parties.
The first is generational turnover. Those born after the 1970s (roughly, the Millennials) have the highest rates of affiliating as Independents rather than Democrats or Republicans, and have the highest desire for a new party to emerge. This is a true generational cohort effect, as it remains true no matter how old they are when you poll them -- the same holds for the Boomers being the most stridently partisan, which holds no matter at what age you poll them. (Data from the General Social Survey.)
Do they want a permanent third party of roughly equal influence to the other two existing ones? Or do they have in mind a new party to replace one of the existing ones altogether? If that's what they're thinking, then it would be the Democrats that they'd be targeting. They are more frustrated Democrats than frustrated Republicans, so they're looking for something that's definitely anti-Republican, but that doesn't suck so pathetically as the Democrat party does.
The second is that we're in an era of partisan polarization that has only been this high during the lead-up to the Civil War (see Peter Turchin's Ages of Discord). Separately, there are 50-year cycles in collective violence (such as riots), with a peak coming circa 2020. That certainly sets the stage for something similar to the Civil War, rather than any old changing of regimes. The transition out of Reaganism and into Bernie-ism will be far more disruptive and violent than the transition out of the New Deal and into Reaganism.
With that intense level of regime change, it could result in a whole new party that triumphs over the old dominant party, in the same way that the Republican party was born during the Civil War era, taking the place of the earlier Whig party as the opposition to the Jacksonian Democrats.
If the historical analogy holds up this time -- and admittedly we only have one previous time period to examine -- the old dominant party will be the Reaganite Republicans, who will continue to formally exist but who will get shut out of power for several decades as the triumphant post-Civil War 2.0 party lays a whole new foundation. The new dominant party will come out of the old opposition to the Reaganites, namely the Democrats, and will replace them as a new second party. Call it the Populist party.
It's not that hard to imagine, given that Bernie or someone like him is the only viable candidate in the next elections to oppose the Reaganites. Since he's not really a partisan Democrat, that would replace the Dems at the presidential level. And Lord knows the Dems have already shut themselves out at the state and local level during Obama's two terms.
That would only leave the Congressional Dems to re-affiliate with the new Populist party -- and if they want to win back Congressional seats that they've lost, they might as well re-brand as an entirely new party, to make sure the stink of Pelosi and Schumer never gets stuck to them in the first place. If they want to pick up more seats in the South, or the Rust Belt, a Populist party would stand a far greater chance at unseating Republicans than the Democrats would.
It still could happen that the regime change will be a re-alignment and triumph of the Democrats, but I think the context being something akin to the Civil War will make people feel more like a revolution -- a word Bernie and his followers are fond of in their branding. Making a decisive break with the polarized past -- not just the old dominant party, but the milquetoast opposition that squandered its chance to rein in that dominant party.
Sometimes the can that the weak opposition kicked down the road is something banal like marginal tax rates or cultural values, and they can be forgiven for punting. But when they punted on something that can shred the societal fabric to the point of civil war, like corporate elitism and globalization, the old opposition will look so irresponsible that they cannot be trusted to lead the way out of the carnage.
Here's to hoping that I get to keep Democrat blood off of my hands and only cast presidential votes for Nader '00, Trump '16, and an Independent / Populist Bernie ticket in 2020.
* Contra libertarian-leaning folks like Peter Schiff, who also see this happening, I think the Bernie politicians would make major cuts to federal government spending -- like not inflating multi-trillion-dollar finance bubbles to benefit Wall Street and Silicon Valley or military bubbles to benefit the Pentagon and the CIA. The Bernie people's forerunners were the New Deal Democrats, and they did not balloon the debt, let alone term after term. They were not permanently at war, there were no too-big-to-fail banks to bail out, and taxes were a lot higher.