I’ve been bracing myself for the strangest Election Day ever, but I have a nagging feeling that I’ve been here before, and not that long ago.

After voting to Remain on June 26, 2016, I decided to stay up a bit later than normal to watch the first results of the EU Referendum come in. I had moved to London from Brazil when I was 19, and after living here for some time, I chose to get my UK citizenship in 2015 because I believed it to be an inclusive and multicultural society. And as someone who holds an additional two passports–for the US and Italy—I know what those kinds of communities look like. Needless to say, I was very invested in my newly adopted country’s vote.

Seven hours later, I was still watching the slow-motion car crash that was Brexit unfold in all its (in)glory. As I finally crawled into bed just after five in the morning, I was still clinging to a last shred of hope; maybe when I woke up I’d find there had been some error with the counting, or something, anything. But the UK had no such luck. My generation will have to deal with the fallout of that Brexit vote for years to come.

Although polls suggested that 73% of young people supported Remain, turnout in that crucial age group was as low as 36%.

And it is my generation—the millennials—that I blame. As much as the UK’s decision to leave the EU represents a victory for closet racists, self-serving politicians, and angry masses sick of being ignored by “the elite,” it was ultimately the laziness and arrogance of the younger generation that I believe allowed this to happen. In the UK, although polls suggested that 73% of young people supported Remain, turnout in that crucial age group was as low as 36%.

American millennials should take notice, lest they make the same mistake and find themselves waking up on Nov. 9 with a hangover and the grim yet inescapable reality of a president Donald J. Trump. (I’ve already done my part and sent in my absentee ballot weeks ago.)

Millennials like myself tend to be global citizens. We might have one place we consider to be our primary home, but that’s not necessarily where we were born, or where our parents came from. We move around a lot, change jobs often, have a different concept of ownership, and use technology to connect us to people wherever they happen to be. All this comes with a hardwired understanding that we live in an interconnected world—a world where building giant walls to keep foreigners out is not the answer to all of society’s problems. The digital economy transcends borders, and collaboration, as in the free exchange of talent and ideas, is what drives its growth. To borrow Thomas Jefferson’s words, we hold these truth to be self-evident.

But over the course of this bewildering US presidential campaign, it’s become frighteningly obvious that over 40% of Americans do not see the same reality as I do. Like in the UK, large swathes of the US population feel such a sense of social injustice and acute desperation that they are willing to follow just about anybody who promises to lead them to a better place—whatever that place might look like. This burning anger feeds opportunists like Trump, much as it did his buddy Nigel Farage in the UK.

We don’t have the luxury to leave the voting for someone else, because, quite frankly, we’re it.

We millennials look at the poisonous, nonsensical rhetoric politicians spew out and think ourselves safe, because no sane person could actually take such people or ideology seriously. Because who in their right mind could vote for someone like that? Surely the joke’s up—it’s been fun, but now it’s time to stop pretending we’d appoint a man who’s been caught on tape bragging about grabbing women by their genitalia to the highest office in the land. Let’s leave the rabbit hole and return to sanity.

Heck, if everyone can see this plan is crazy, we probably don’t even need to bother voting, right?

Wrong. In spite of everything Trump has said and done, 40% of Americans—the so-called “unswayables”—still plan on casting their vote for him today. Then there are the quiet ones, who won’t admit to supporting Trump but will still vote for him when alone in the voting booth. (Some of these same people are likely convinced that the system is permanently rigged against them, and although it is unclear how many of them will be recruited as “ Election Observers, ” the threat of intimidation and racial profiling may be enough to put off many Hillary Clinton voters.)

There’s no question that this election will come down to an incredibly narrow margin, and which way it goes will ultimately depend on who bothers to show up. Young people don’t have the luxury of leaving the voting to someone else, because, quite frankly, we’re it. There are over 69 million millennials in the US today, and we’ve recently overtaken baby boomers as the largest voting-age demographic. But we also tend not to exercise that awesome power, and consistently have the lowest voter turn-out of any age group. If we choose not to exercise that very real power today, it could mean the democratic experiment America was founded on will have failed.

The liberal media that Trump so often whines about is somewhat complicit in this. Treating the election result as a foregone conclusion is the worst thing we could do right now. When I saw the Saturday Night Live debate spoofs—which were undoubtedly satiric masterpieces—and heard them referring to “president Hillary Clinton,” I cringed. It’s just this sort of establishment smugness that can galvanize Trump voters and lull those optimistic millennials into a false sense of security. We’re not over the hill yet.

If we get lazy and self-indulgent now, our complacency will hand Trump a win—and then we all lose.

Like many of my fellow millennials (and this distraught little boy), I’m really going to miss current US president Barack Obama. But it’s time to snap out of it, to stop pining over Bernie, and to quit moaning about Hillary. If we get lazy and self-indulgent, our complacency will hand Trump a win—and then we all lose.

Similarly to the sentiments of Michael Moore, I have never wanted to be proven wrong more than I do right now. But until I see Hillary safely sworn in at the White House, I won’t shake off the deep sense of foreboding that the US will follow the UK’s path.

The world has changed a lot this past year, and not for the better. Not that long ago, my four passports seemed to afford me endless options. Now, faced with the prospect of a Trump White House on top of a Brexit Britain (not to mention Brazil’s rampant corruption scandals and Italy’s deep economic crisis), it’s looking like I’ll have to join Bryan Cranston in Canada. (Or, maybe not.) I hear Vancouver is really nice this time of the year.