President Donald Trump made headlines at the UN with his denunciation of Iran and North Korea. They deserve all the presidential condemnation they get. But the fact remains that Iran and North Korea are UN member nations. And that sums up a fundamental problem.

The UN today is a club for nations. Every widely recognized nation is in it, and if you’re not a nation, you’re excluded. As such, the UN has no serious membership standards: If you’re a nation, you’re in. But that was not how it was meant to be. When the UN was founded in 1945, it was a society for the nations that had won the Second World War. The losers — Germany, Italy and Japan — were excluded. As such, the UN was supposed to embody the values America had fought to defend.

Those values were summed up in the preamble to the UN Charter. It doesn’t make elegant reading, but it shows that membership of the UN was intended to stand for something. UN members were to be its gatekeepers, responsible for keeping out nations that couldn’t live up to the UN’s values.

In practice, this system was broken from the beginning by the inclusion of the Soviet Union. Given its role in winning the war, this inclusion was inevitable but tragic, because it meant the gatekeeping system couldn’t work. A UN built on the USSR was never going to stand for democratic values.

What was more tragic, though, was the way the USSR’s inclusion affected the international system erected after 1945. Partly because of the precedent set by the USSR and partly because of the Cold War between East and West, that system included most and excluded few — and as time went on, even fewer.

The end of the Cold War gave this vision the opportunity to stretch its legs. The guiding words of the era were inclusion and engagement. The way to remedy the sins of the bad was to give them a room in the house of the good. North Korea’s admission to the UN alongside South Korea in 1991 was symbolic; a brutal dictatorship and a thriving democracy walked in side by side.

For a time, 9/11 put the brakes on the engagement fad. The cost we had paid by refusing to confront the Taliban in the 1990s, coupled with the risks posed by uncontrolled programs for weapons of mass destruction, made the get-along-go-along approach seem too dangerous to risk.

But ultimately, foreign policy reflects domestic culture. In today’s West, the most damaging accusation you can make is that someone has been treated unequally, especially if this results in exclusion from benefits. Unequal treatment has become synonymous with bias, prejudice and evils of all sorts.

A society obsessed by equality finds it hard to have a foreign policy that reflects the fact that treating different behaviors differently is a sign of sanity, not bias. The pull to inclusion and engagement in today’s society is immense.

Occasionally, signs of sanity appear. Last week, 17 national anti-doping organizations, including the United States, demanded that Russia be banned from the 2018 Winter Olympics. Russia engaged in systemic doping at the 2014 Games, and it’s still concealing evidence.

Such signs offer a little hope, if only a little. While efforts to reform international institutions like the Olympics from the inside aren’t a waste of time, reforms won’t stick unless we get back to the simple idea that institutions should have standards for membership. If you can’t abide by them, you’re out.

Many liberals disliked seeing Trump address the UN. Yet in his audience were a lot of presidents for life — dictators. Dislike Trump if you will. But save the contempt for the vision of inclusion that assembled his audience.