President Obama speaks at a news conference following the Group of 20 summit in Antalya, Turkey, on Nov. 16. (Ozan Kose/Agence France-Presse via Getty Images

Here's President Obama on the hardest lesson he has learned in office: "You can’t separate good policy from the need to bring the American people along and make sure that they know why you’re doing what you’re doing. And that’s particularly true now in this new communications era."

That admission came during a sit-down Obama did with HBO's Bill Simmons for a spread in GQ magazine, which named the two its men of the year. Obama acknowledged to Simmons that in the first few years of his presidency, "a certain arrogance crept in, in the sense of thinking as long as we get the policy ready, we didn’t have to sell it."

Yup.

Obama's comments should be sent to every politician, poli-sci major, political scientist and political reporter in the country. And they should be required to print them out and post them somewhere they can see every day. Why? Because they debunk one of the most pervasive — and incorrect — narratives in American public life: That somehow you can — and people do — separate policy discussions from the raw political calculations that undergird them.

This line of thought holds that "real leaders" think nothing of the political landscape on which their policy decisions fall or the political reverberations for them (and their party) of those decisions. It supposes that policy is a clean and noble pursuit, unsullied or besmirched by the low arts of politics.

Which is, of course, a load of bull. There is politics in every single policy decision made — and not made — by every politician in this country. Every single one. (If you don't believe me, watch "Lincoln.")  And, if ever there isn't political calculation not only in the decision-making process but also in the execution of the strategy to sell that policy to the public, that policy will struggle to gain widespread public acceptance.

Take Obamacare, which is without question the policy Obama is referring to when he talks with Simmons about putting something out in the public without worrying about the politics of it all. Obama, the White House and Democrats badly lost the message war over the Affordable Care Act, which led to, among other things, the election of Scott Brown in a 2010 Massachusetts special Senate election and the massive legislative gains made by Republicans in the 2010 and 2014 midterm elections.

And, even five years removed from the main legislative fight over the law, opinions about Obamacare remain deeply divided and tilting negative. This chart comes from the Kaiser Family Foundation:


The discontent over the law had/has little to do with the specifics of the law and much more to do with people's perception of the law: that it was a government overreach that would make things more complicated, not less so. The law's specifics — keeping kids on their parents' insurance until age 25, no denials of coverage for preexisting conditions — consistently polled well above the law as a whole.

Obama's failure to acknowledge the hand-in-glove relationship between his policy proposal and the politics of selling a health-care overhaul to the country cost his party both chambers of Congress and more than 900 state legislative seats. (Of course, health care wasn't the sole reason Democrats lost so badly in 2010 and 2014, but it was where it all began.)

Policy might be the bones of our democracy. But politics is the muscle and tendon that binds it all together. You can understand how policy moves (or doesn't) only if you understand the politics that motivate each politician involved in the development of that policy. There is no one without the other.

Obama gets that — albeit after learning it in a way that left many congressional Democrats on the outside looking in. Now, all we need to do is convince the rest of the policy world.