Jill Filipovic is a journalist based in Washington and author of the book " The H-Spot: The Feminist Pursuit of Happiness ." Follow her on Twitter . The opinions expressed in this commentary are solely her own. View more opinion articles on CNN.

(CNN) It was a dark day for the world Tuesday. We awoke to find the President of the United States using his massive social media presence to mock a child whose only crime was trying to make the world better (and to maintain its existence).

We learned a damning story from the New York Times of the Trump administration's indifference to the potential arrest and imprisonment of a Times reporter in Egypt -- the kind of antipathy toward the press that would have been unthinkable pre-Trump, and now puts us more in league with the demagogues of the world than the democrats.

And at the UN we watched as the leader of the free world delivered a sleepy, low-energy speech that zeroed in on one head-spinning conclusion: every nation should go at it alone

This last, in particular, was a predictable but still distressing message from the erratic President of a nation whose leadership is increasingly irrelevant on the global stage. The United States has never been a perfect place, but in the aftermath of world wars, we were at least an (admittedly imperfect) symbol of liberal democracy.

Now, not even the American President will stand up for liberal democracy, nor a founding mission of the United Nations: to promote peace through interconnectedness.

"The future does not belong to globalists," Trump said in his speech. "It belongs to patriots." He emphasized his administration's program of "national renewal" and took swipes at migrants, portraying them both as victims of violent human traffickers (and the greedy NGOs that enable them, in his telling) and destructive forces that destroy societies and undermine prosperity.

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Trump's view was one of hyper-nationalism, of each nation advocating only for its own people, closing down its borders, drawing hard lines between "us" and "them." "The future belongs to sovereign and independent nations who protect their citizens, respect their neighbors and honor the differences that make each country special and unique."

We know, historically, that this kind of inward-looking nationalism is often the precursor to conflict. Interconnectedness through the movement of people and goods creates incentives to deal with conflicts peacefully; it encourages leaders to pause and consider consequences rather than reacting rashly; it spreads out self-interest, leading to better outcomes for all involved.

Trumpian nationalism, on the other hand, is dangerous to world peace. It places a higher value on the lives of your own countrymen than on human life more generally. It suggests that naked self-interest is more beneficial than collaboration. It is hard to see how this does not set us on a course toward conflict.

It's also a dangerously outdated view in a world where we are in fact more connected and mobile than ever before. The internet and social media (which America's Twitter President also disparaged in his speech) allow us to virtually border-hop and see life beyond our own national, cultural and ideological boundaries. Travel is cheaper and easier than it's ever been, and people are increasingly voting with their feet, seeking work and safety in other nations.

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The problems we face are similarly collective. Climate change, for example, is exacerbated by some countries more than others, but is a global problem that no nation can solve alone. Nor can any shoulder the burden alone.

But Trump isn't looking forward. He is looking backward. He used his platform at the UN to toss the usual red meat to his conservative base -- opposition to abortion and socialism, a staunch defense of guns and religion (though he failed to mention his 2017 executive order suspending entry into the United States for citizens of several Muslim-majority countries) -- while recasting American values away from promise and equality and toward smallness, fear, and paranoia disguised as patriotism.

It was a sad moment to see the American President fit right in between other autocrats and wannabe strong men, from Brazil's Bolsonaro to Egypt's Sisi to Turkey's Erdogan, all of whom took the stage this morning and all of whom have trampled the civil rights and freedoms of their citizenry.

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Tuesday morning at the UN was a chilling look at where men like Trump can take their nations.

It's not too late for the United States to meaningfully lead again, and to embrace the ideals that do make us great: A respect for human rights, a dedication to international cooperation, a commitment to democracy and freedom. All of those principles are under attack from our current President, both at home and abroad. It was a shame to see him take his dangerous plans to the world stage. And it makes voting him out of office more urgent than ever.