From “The Daily” newsletter: One big idea on the news, from the team that brings you “The Daily” podcast. You can sign up for the newsletter here.

The idea that America is in decline isn’t new.

For decades, academics have warned that partisan gridlock, politicized courts and unfettered lobbying were like dangerous substances — if taken in excess, America’s democratic systems were at risk of collapse.

But what happens when the idea itself gets mainlined? When words like “died,” “decline” and “dagger” sit near “America” on front pages across the country? When a majority of the American public rewrites the story they tell themselves about their country’s standing in the world?

That’s what some experts say is happening now — that the Capitol riot and its aftermath have normalized a sense among Americans that the country, its economic system and its standing in the world are in decline. New data supports this claim: 70 percent of Americans believe the U.S. is “in crisis and at risk of failing,” according to a recent poll.

Fortifying America’s democracy is not just about ensuring the trustworthiness of elections, but also about safeguarding Americans’ belief in the possibility of change. So what happens when that self-conception falters — when Americans begin to believe their country isn’t winning, but instead is losing a long battle?

“Jan. 6 and then the Republican reaction is a really important turning point in the perception of American decline,” said Francis Fukuyama, a political scientist and author. Mr. Fukuyama noted that while he had been writing about American political decay for years, the concept had assumed more systemic import after the Capitol riots — and wider acceptance.