In an interview on Wednesday, MSNBC’s Chris Matthews asked Gary Johnson to name “one foreign leader that you respect and look up to.” The Libertarian Party nominee for president came up blank. “I guess I’m having an Aleppo moment,” he said, referring to an interview blunder earlier this month when he revealed his ignorance of the war-torn Syrian city.

Perhaps this might not hurt Johnson with the demographic that he is polling best with right now: millennials. After all, the Libertarian Party is against foreign intervention of any kind, and many young people today are quite skeptical of our military entanglements. Moreover, there are other issues—abortion rights, LGBT rights, criminal justice reform—where the interests of millennials and those of the Libertarian Party seem to align. 

Yet on a host of others—some very serious issues which millennials hold dear—Johnson is utterly out of step with this demographic. He doesn’t think the government should do a lick about climate change. He supports TPP, Citizens United, and unapologetically opposes all forms of gun control. Obamacare? Johnson says only the free market should be involved in health insurance. On perhaps the biggest issue among younger Sanders supporters—free college tuition—Gary Johnson will offer them nothing. That’s Libertarianism for you.

But if so many of Johnson’s positions are anathema to millennials—polls confirm that millennials want way more government involvement on these issues, not less—why does he still poll so well with them? Is it simply that the appeal of voting against the two parties in this anti-establishment year—a “pox on both your houses” approach—is so strong with this age group? With fewer of them registering as Democrats or Republicans—a plurality now proclaim themselves independents—this might ring true. Or could it be, as some suggest, that it all just comes down to legalizing weed, something Johnson has repeatedly called for? 

That any voter would prioritize legal marijuana as their number-one issue, particularly in the year of Donald Trump, seems absurd. But if we dismiss this analysis as cynical, we are still left wondering if the liberal millennials who support Johnson are even aware of the Libertarian Party platform positions. And if they are aware, and see their vote as a way of protesting against the status quo, then one has to wonder if they understand the consequences of voting for someone whom they don’t agree with on the issues just to send a “message.”

There’s only one obvious candidate for younger voters: Hillary Clinton. Her positions, among the general election candidates, most closely align with millennials’.  Spurred on by Sanders, she has moved decisively to the left—on trade and college tuition, notably—since the beginning of the primaries. It’s fair to say that she’s to the left of Obama.

That conclusion is even more perplexing because a healthy majority of millennials—62 percent in a recent survey—approve of Obama’s performance, the highest approval rating among age groups. And yet many of these same people find themselves lukewarm to Obama’s obvious heir, the only person who would continue his policies. Clinton’s entire campaign has put as little space between her and Obama as possible, and the president and first lady both have repeatedly hit the campaign trail in recent weeks to hammer home just how much their legacy is on the line. 

It’s easy to argue that millennials approve of Obama because they feel connected to him. He inspired their loyalty, and much like the passion that Sanders inspired in so many of them, these kinds of feelings are simply non-transferable. Clinton is, by her own admission, not a great orator. She doesn’t exude charisma. She’s more of a workhorse. But is this lack of “connection” worth putting at risk the causes they most believe in? Isn’t that the very definition of voting against your own best interest?

Perhaps millennials—many of whom will be voting for the first time—have different ideas about the purpose of voting. Certainly a lot of people see voting simply as an act of personal choice, a way for us to express our allegiance to candidates we feel connected to. But is that really all there is to voting, or should we have more of a sense of civic responsibility? Should we, when we go to the ballot box, strive to think about the broader consequences of our actions, and whether or not we are promoting a greater societal good? Certainly Sanders has made it clear that, because of the unique threat Trump poses, this is not the year for third-party candidates. Some millennials are too young to know who Ralph Nader is and how close Al Gore came to winning the 2000 election, but they aren’t too young to know about the Iraq war, or the 2008 recession and its aftereffects. 

For millennials in swing states who care about progressive causes to choose Johnson, or Green Party nominee Jill Stein, or even abstain from voting, is akin to saying, “I am too progressive to vote for Clinton, but not progressive enough to stop Trump.” These young voters seem to be attributing too much significance to the act of choosing Clinton with their vote, and not nearly enough to the act of stopping Trump, something which can only effectively be done by doing the former. There is no denying that a Trump victory would be a devastating blow to the progressive cause. The Supreme Court already has one vacancy; at least one, if not two more vacancies, are likely in the next four years. Trump has already outlined the kind of constitutional conservatives he will nominate to the court. If Republicans hold the Senate and House, a President Trump could repeal Obamacare, defund Planned Parenthood, approve tax cuts for the rich, undermine the EPA, and so on. 

Still, for many millennials, these reasons don’t seem convincing enough to vote for Hillary. Perhaps they do not view Trump as the existential threat that so many others, including many Republicans, view him as. Perhaps they are misinformed about Clinton’s record or her positions. Or perhaps, after a bruising primary fight where many of the right’s specious allegations against Clinton were raised by those on the left, they have been poisoned by what they believe is the truth about Clinton.

Because if Clinton is unacceptable to so many millennials despite her positions—if a majority of young people are aligned with her on the issues, and still they refuse to vote for her—then for all intents and purposes, these voters are not acting in their best interests. They’re acting irrationally. Millennials who chose to vote for Johnson will certainly have their voices heard at the Ballot Box, but if Trump wins, they’ll find their voices stifled for the next four or even eight years.

This article has been updated.