DAVID BREWSTER: It’s clear that democracy is under threat in U.S., but here’s evidence of the decline in democracy, and belief in democracy around the world, and particularly with younger voters. Researchers have developed a 3-step measurement for stability. “The first factor was public support: How important do citizens think it is for their country to remain democratic? The second was public openness to nondemocratic forms of government, such as military rule. And the third factor was whether “antisystem parties and movements” — political parties and other major players whose core message is that the current system is illegitimate — were gaining support. If support for democracy was falling while the other two measures were rising, the researchers marked that country “deconsolidating.”