No wonder the so-called mainstream media has trust issues. In the search for ratings and Internet traffic, it gives voice to the same fearful hyperbole found elsewhere in society -- and often plays it for entertainment value. (Witness the rise of Donald Trump, political pundit and almost-candidate, whose regular proclamations headline the New York tabloids and are then repeated throughout cable news.) It's the classic case of preying on our insecurities, points out Ari Kohen, a political science professor at the University of Nebraska.

"Like those teases for the 10 o'clock news: 'What household product might be making you sick? Tune in at 10!' It's the same idea," he says.

Throw in the echo chamber of right- and left-wing websites, and these claims are even harder to escape, particularly in what's been described as "the post-truth era."

"It's almost as if everybody's creating his or her own reality at this point," says John Carroll, a Boston University communications professor and regular media commentator. "They can essentially construct an information environment that's so self-reinforcing, and so exclusionary, that they don't really have to consider any evidence that contradicts what they already believe."

'We're in the danger zone'

American history has not been kind to the conspiracists. In general it has fought off their claims, laughed at their theories.

But there have been times when the suspicious have had a point. As the old saying goes, just because you're paranoid doesn't mean they're not out to get you.

After all, the Soviet Union did infiltrate some U.S. agencies, and Julius Rosenberg really did deliver classified information. The CIA was instrumental in a number of coups. The FBI's COINTELPRO program spied on domestic groups. Watergate revealed a tangle of Nixonian malfeasance. A handful of climate scientists did try to clamp down on dissent. (Their opponents have also worked together.) Finance industry workers did cover up bad loans and, more recently, fix the LIBOR rate.

All are "clear evidence," says Fordham University professor Bruce Andrews, who has taught courses on conspiracies and covert activity, "of actual organized groups doing things."

The dark currents can give a person pause.

"One of the reasons conspiracy theories have proliferated over the last half century is that they have so often been proven correct," says Assumption's Vaughan.

It may never hurt to have a healthy dose of skepticism. But, a willingness to accept -- or immerse oneself in -- mistrust has been shown to weaken civic structure in other cultures. Russia and some countries in the Middle East have suffered from a lack of transparency, along with great divides between the haves and have-nots. Those cultures also have long histories of conspiracy-mongering and little trust in their governments.

The United States was intended to be different.

"America's ability to question and, if necessary, change our government made such (conspiracy-minded) thoughts here against the grain," says Villanova's Arnold.

Despite our weakened faith in government and institutions, the country chugs along. But what of the future? "I wish I could be optimistic, but I really can't," says Reiss, the San Diego psychiatrist. "There's so much power behind making things destructive. It's really in the service and to the advantage of the politicians on both sides to keep people in a somewhat scared state."

"(Consensus) is not dead, but we're in the danger zone," says Avlon. "There are real costs to hyperpartisanship. Most importantly it becomes ultimately a threat to self-governance -- it's stopping us from being able to solve the serious problems we face."

"Righteous Mind" author Haidt, however, sees a reason for hope -- though not immediately.

We're stuck for probably the next five years, he says. After that, events could intercede. We could face economic collapse; we could have total victory by one party. But the most intriguing, he observes, is the passage of generations.

"We went from the Greatest Generation, which was the most civic-minded because they fought World War II together ... to the baby boomers, who were the worst at working together because their foundational experience was splitting apart to fight the left-right battle," says Haidt. "We'll soon be moving on to the millennial generation, which is marked by a reluctance to make moral judgments."

That has its own drawbacks, he adds, "but some tolerance and reluctance to judge might be just what we need in the 2020s."

Until then, however, there will be no golden age of understanding, no rebirth of trust. No, for now, we're stuck with the system we have, the noise it creates, and the voices in our heads.