If you want to understand why politics is devolving into a demagogic spectacle that is endangering liberal democratic government throughout so much of the world — from the U.S. to Brazil, Italy, Poland, Hungary, and beyond — you could do worse than study the way the story of the migrant caravan has unfolded in American political culture over the past week.

The caravan itself — the way it's being portrayed in the media and manipulated by the president and his party, and the response to all of it on the part of the Democrats — encapsulates everything that's going wrong with politics in 2018. Let's take a look at three of the guilty parties here.

1. The charlatan-demagogue in the White House

Roughly 7,000 people (most of them Hondurans fleeing poverty and violence in their home country) are walking north through Mexico toward the southern American border over 1,000 miles away. This, says President Trump, constitutes a national emergency. Never mind that the caravan adds up to just 0.7 percent of the roughly 1 million people who will immigrate to the United States this year — or that there is zero evidence for Trump's race-baiting claims that "unknown Middle Easterners" are "mixed in" with the caravan.

What makes these 7,000 noteworthy is that they are traveling as a group (in part to protect themselves on the dangerous and grueling journey) and images of their movement are plastered across televisions, computer monitors, and the front pages of newspapers throughout the U.S., accompanied by blatantly false and alarmist assertions on the part of the president and his propaganda ministers in the right-wing media.

Not only do these migrants amount to a miniscule number in the context of present immigration rates. They are also microscopic compared to the ocean-going "caravan" of 5.3 million Italians, 2 million Central European Catholics and Jews, 1.5 million Scandinavians, and millions of others who traveled to the United States on ships and made a home for themselves in the United States between the 1880s and 1920s, at a time when the population of the country was a third of what it is now.

None of this means that American immigration policy can't or shouldn't be changed, adjusted up or down, if Congress can only get its act together. Such changes are perfectly legitimate. But treating a modestly sized group of people seeking to make a better life for themselves in the United States as some kind of existential threat to the country is both morally outrageous and an expression of world-historical cowardice on the part of the president. But it's a form of cowardice tailor made to appeal to timorous Trump supporters, and they appear to be responding appreciatively to the message.

2. The self-defeating open-borders activists

The migrant caravans that now regularly make their way to the U.S. from the south are normally organized by a group called Pueblo Sin Fronteras (People Without Borders), which explicitly calls for open borders and the free movement of people without restrictions. Though the group apparently didn't directly organize the current caravan, it has provided logistical support, with affiliated activists in Honduras, Mexico, and the United States pushing its open-borders position.

This plays right into the hands of nationalistic xenophobes like Trump and his media cheerleaders, who can point to an ideological agenda behind the caravan that they (justifiably) see as incompatible with the exercise of national sovereignty in the United States. If those who favor a liberal immigration policy hope to prevail, they need to combine that position with an acceptance of the legitimacy of sovereignty and borders — with Americans consciously choosing to accept a high number of immigrants. The quickest and surest way to ensure that severe immigration restrictionism prevails in the United States would be for those who favor a more liberal immigration policy to adopt the explicitly open-borders position that Trump (falsely) claims they already favor.

3. The paralyzed Democrats praying the issue goes away

The Democratic Party as a whole doesn't favor open borders, but a growing share of the party is much further to the left on the issue than was typical just a decade ago. The result is a party deeply divided — sympathetic to the migrants, convinced that immigration is good for the country, but also terrified of being portrayed by the president as welcoming throngs of potentially dangerous and destabilizing outsiders to the country without restriction. That's one reason why so many Democrats appear flummoxed about how to respond to the caravan and so prefer to say nothing at all, hoping the story will just miraculously vanish between now the midterm elections on Nov. 6.

But there's another reason as well. As David Brooks notes in a recent column, the Democrats are a materialist party that's far more comfortable talking about the details of public policy and social programs than tackling issues of culture — in part because when culture is raised, the party splinters into its component ethnic, racial, and gender identity groups, each one of which prioritizes its interests and outlook over the others, as well as over considerations of the common good. That leaves no one on the Democratic side to forthrightly repudiate the Trumpist line on the caravan by making an unapologetic case for the United States as a country that's easily strong and confident enough to welcome people from other places and transform them into Americans.

Put it all together, and we're left with a perfect storm of ugliness, civic breakdown, and dysfunction — with maximalist demagogues encouraging and empowering one another on either extreme, and no one standing up for a more sustainable and broad-based consensus on which a fair-minded and reasonable policy on the migrant caravan might be constructed.

It's unlikely to end well — for the migrants no less than for America.