PITTSBURGH — Come November, as Democrats try to capture Pennsylvania's state legislature, four of their nominees will be socialists — members of the Democratic Socialists of America. Three of those four are unopposed.

All four women, Summer Lee and Sara Innamorato from the Pittsburgh area, and Elizabeth Fiedler and Kristin Seale of Philadelphia, are first-time candidates who received organized, efficient and professional support from their DSA local chapters. Only Seale faces an opponent, Republican incumbent Rep. Christopher Quinn of Delaware County.

DSA is following the same model here it did in New York, where socialist Alexandria Ocasio-Cortez, another first-time, female candidate, defeated incumbent Rep. Joe Crowley in the Democratic primary. These races have all occurred in urban-centric districts.

For some professional Democrats there is a private sense of panic. Those more familiar with the eternal cycles in politics recognize that the party is going through a natural course in the shadow of losses, big and small: rebellion, realignment, and repudiation of the status quo.

[Also read: Socialism is back, and it's taking over the Democratic Party]

The results spilling out of this process have not only caught voters and the media by surprise, they have also caught the Democratic establishment by surprise as well.

But should it have really been that surprising? Have they not been listening to their base? More importantly, have they not been listening to young people who have decided the only way to win as a Democrat is to adopt leftist socialist sentiments and platforms espoused by Bernie Sanders?

Too many Democrats and the professional class spent too much time dwelling on why Hillary Clinton lost for the past two years, instead of wondering and exploring why Bernie Sanders almost won.

There is a very decent argument to be made if the Democratic Party did not have their superdelegate process in place (a body completely made up mostly of former and current establishment elected officials), Sanders could have walked into the convention in Philadelphia on par with Hillary Clinton and faced a floor vote in 2016 for the nomination.

Hard to believe that everyone seems to have forgotten the vivid images of platoons of Sanders delegates at the Philadelphia Democratic National Convention walking out in unison at the very moment when party unity was supposed to marry.

At the time, most reports brushed off the moment because no one of national prominence was involved in the moment, no elected officials, no rock stars, no late-night comedians.

For the political class, they were nobodies; decentralized, mostly young and likely to never to become part of the Democratic club. Two years later, they are organized and trying to dismantle the club.

When your guy/gal loses that way, resentment builds, especially if your establishment keeps talking about why she then lost the general election where she was supposed to be a shoo-in. If you keep ignoring the loose ends who feel ignored, or disrespected, or unappreciated, they will form a movement. And sometimes that movement gets organized, gets motivated, and starts running candidates.

And then they start winning.

The conservative populist coalition that placed Donald J. Trump in office in 2016 did not happen overnight. Certainly he did not cause it. He was just the result. As the Republican Party faces its own growing problems with their new coalition that includes many former moderate to conservative New Deal Democrats sharing the same space with fiscal Republicans — the Democrats’ new coalition includes socialists along with liberals and progressives all trying to share the same objective: winning.

It is something that has been building since the day after Barack Obama won his 2012 re-election and young voters became dissatisfied that he was not left enough on issues like free college tuition, universal healthcare and abolishing Immigration Customs and Enforcement.

Party realignments never pause, they are always in motion. The motive cause acts from the bottom up, not the top down, which is why the political class missed what was forming on the Republican side since 2006, and are just awakening to what began in 2012 on the Democratic side.

Last Tuesday, Merriam-Webster tweeted “'Socialism' has been our top search since Alexandria Ocasio-Cortez's primary win last night.”

It likely won’t be the last time, as the Democrats figure out who is and isn’t part of their new big tent. One thing is for certain, there is nothing stagnant about America’s political parties; about every 60 to 100 years or so, they always realign. It just isn’t always pretty. And while it may not always upend the status quo permanently, it certainly moves it in its direction.

So welcome to a Democratic Party much further to the left than Bill Clinton or Barack Obama ever imagined.

[Related: Socialist candidates the 'future of our party,' says DNC Chairman Tom Perez]