“Bernie Sanders or Bust” has long been the guiding principle of the millennials among Bernie Sanders’s base. Young voters are tired, it seems, of the “lesser of two evils” argument that has so often been used to pressure voters into choosing a less-than-ideal candidate.

This year, the argument has become more prominent, given the looming threat of Donald Trump.

Many prominent supporters of Bernie Sanders have publicly called for Sanders supporters to embrace Hillary Clinton as the Democratic nominee, given the potential dangers posed by a Trump presidency.

Indeed, earlier this week, Bernie Sanders himself made a version of this argument in his first formal endorsement of the former secretary of state.

“In terms of the presidential election this November, there is no doubt that the election of Donald Trump as president would be a devastating blow to all that we are fighting for,” Sanders wrote.

That is why, he added, “I endorsed Hillary Clinton to be our next president. I know that some of you will be disappointed with that decision. But I believe that, at this moment, our country, our values, and our common vision for a transformed America, are best served by the defeat of Donald Trump and the election of Hillary Clinton.”

Many Bernie Sanders supporters have expressed their disappointment at this decision; some see the endorsement as capitulation to a system that is inherently corrupt, overflowing with the corporate money that Sanders has, throughout his political career, so passionately condemned.

For Hillary Clinton, Sanders’ formal endorsement would seem to be a positive step in courting the Vermont senator’s enthusiastic supporters — but Sanders backers, according to recent polls, have different plans.

According to a new poll released on Thursday, almost half of Bernie Sanders’s millennial supporters — 48 percent — now say that they will vote for a third-party candidate over the two widely disliked nominees of America’s two major parties.

NEW POLL: Nearly half of Sanders' millennial supporters would vote third-party https://t.co/TBluDq5xPK pic.twitter.com/rlzgfPXLre — The Hill (@thehill) July 14, 2016

This is consistent with previous polls suggesting that a growing number of Sanders supporters, not just millennials, do not plan on casting a ballot for Hillary Clinton in November.

For Clinton, this is a troubling development. It suggests that the distrust reflected by recent survey data is manifesting in the practical choices of potential voters. And it will be difficult for her to convince those who are disaffected by the substantial baggage she carries, from the email scandal to the Wall Street speeches to her support for disastrous interventions overseas.

This revolt against the “lesser of two evils” argument is significant — it demonstrates that young voters are tired of the limits inherent in the two-party system, and it shows a real appetite for alternative candidates and agendas.

Cynically, this can be viewed as a need to be trendy. In reality, however, young voters are reacting to an economy that is working primarily for the wealthiest and to a job market that is increasingly limited, leaving students saddled with loan debt with few opportunities.

Millennials feel that the status quo is no longer enough, and this explains their overwhelming support for the insurgent candidacy of Bernie Sanders, which focused largely on income inequality, corporate criminality, Wall Street greed, and the need to provide services for working families that have increasingly been locked out of the system.

By refusing to vote for Hillary Clinton or Donald Trump and instead opting for an alternative, whether that alternative is Jill Stein or Gary Johnson, millennials are saying what Sanders has said throughout his campaign: “Enough is enough.”

Rolling Stone’s Matt Taibbi argues that the “lesser of two evils” argument is, in many ways, fueling the problem. Republicans, he notes, have increasingly distanced themselves from the needs of the people, and the Democrats have responded by doing essentially the same thing. This has left voters feeling neglected and dissatisfied, fueling either rage or apathy.

“Beltway Democrats,” Taibbi observes, “seem increasingly to believe that all people who fall within a certain broad range of liberal-ish beliefs owe their votes and their loyalty to the Democratic Party.”

Young voters, by refusing to embrace Clinton as the less-bad candidate, are revolting against “lesser evilism.” They are refusing to accept a Democratic candidate whose most compelling political quality (given the widespread view that she is dishonest and untrustworthy) is that she is not Trump.

This, millennials are saying, is no longer enough.

[Photo by Alex Wong/Getty Images]