Barack Obama has met the enemy, and it is us, or at least our diverse, clamorous media environment.

Asked what keeps him awake at night in an interview with CBS News this week, the former president said “the degree to which we now have a divided conversation, in part because we have a divided media, a splintered media.” He noted, “When I was coming up, you had three TV stations … and people were getting a similar sense of what is true and what isn’t, what was real and what was not.” Now, “we almost occupy different realities.”

There is something to this, of course. When three broadcast networks controlled much of the news and there was nothing else to watch and few other alternative sources of information — no internet, social media, talk radio, etc. — it created a shared experience that is never going to be replicated. It’s also true that there is more schlock masquerading as news than ever before, and social media — Twitter, in particular — has had a deranging effect on our politics.

Still, Obama is operating from a flawed assumption — that if only the media were more uniform and we had “a common set of facts,” our politics wouldn’t be so divided.

This gets it backwards. What we have in our politics is a disagreement about values and philosophical premises, from which factual disputes flow, rather than a consensus on first principles that is getting disrupted by disputes over niggling factual questions.

If only we agreed what constitutes a fetal heartbeat, this abortion issue could be settled once and for all is something that no rational person has ever thought or said.

Poisonous disputes about the basics of contentious matters — or as Obama puts it, “a divided conversation” — aren’t anything new in American history. We didn’t agree about what was happening in Bleeding Kansas, or in the early years of the Soviet Union (New York Timesreporter Walter Duranty infamously won a Pulitzer Prize for reports downplaying Stalin’s brutality), or during the Vietnam War.

To take a controversy from the latter, was the Tet Offensive a victory or defeat for the Viet Cong? That’s a rather fundamental question that people have differed about from the beginning. CBS News put its thumb on the scale with anchor Walter Cronkite saying in the aftermath, “We have been too often disappointed by the optimism of the American leaders, both in Vietnam and Washington, to have faith any longer in the silver linings they find in the darkest clouds.” His view was that “we are mired in a stalemate that could only be ended by negotiation, not victory.”

President Barack Obama speaks at a tribute to the late television journalist Walter Cronkite in 2009 at Lincoln Center in New York City.