The assassination theory has collapsed like a house of cards, as its pseudo-experts have been exposed as frauds or fools. And rational, liberal Poland despises “Smolensk folk.” If life went on only in the realm of ideas, you might say rightly so. But neither “Smolensk folk” nor Poland’s hard-line nationalists can so easily be wished away.

You find these new nationalists in busy cities and impoverished backwaters alike. They number among them university math students, graduate engineers and technicians, as well as unskilled workers. These people lack jobs and prospects: One-third of young Poles are jobless. What unites them is anger. They hate the establishment, and they channel their rage through attacks on others: immigrants, gays or Russians.

The prevalence of the “Smolensk religion” has emboldened the ultranationalists. For successive years since 2011, mobs have set fire to immigrant apartment blocks in Bialystok, eastern Poland. In June, at a conference in Wroclaw, a lecture by the veteran leftist intellectual Zygmunt Bauman was disrupted by hecklers shouting anti-communist slogans. At the Independence Day marches, the extreme right is not just permitted but encouraged: Counterdemonstrations have been suppressed and the “patriotism” of the new fanatics is praised.

The great dilemma facing Poland, with an election coming in 2015, is how to halt the rise of the ultranationalists without resorting to illiberal, authoritarian measures like preventive detention, and restrictions on free speech. Fortunately, a movement to counter the far right is stirring: Four days after the Independence Day trouble, the streets of Warsaw witnessed a protest against xenophobia, in defense of diversity — to show that a rainbow Poland does exist.

There is hope of another kind, too. In the play “The Wedding,” the 1901 popular classic by Stanislaw Wyspianski, a pro-independence uprising fails to materialize because a canny farmhand loses the horn he is supposed to sound as the signal to fight. The song that ends the play, “You had the golden horn, you rogue,” suggests a metaphor about lost opportunities, a stern critique of Poland’s partition-era impotence. But reading the play perversely, you might say that our historic shortcomings sometimes turn out well for us.

In Poland, nothing ever really happens to completion. Often, this is our curse, but in the situation that produced the “Smolensk religion” and the new-old nationalists, it might prove salutary.

Artur Domoslawski writes for the weekly magazine Polityka and is the author of “Ryszard Kapuscinski: A Life.” This essay was translated by Antonia Lloyd-Jones from the Polish.