Michael Moynihan points the finger at all of us:

Americans aren’t victims of the supposed "post-truth" era, but gleeful co-conspirators. And unctuous politicians and their surrogates understand that the benefits of lying about your opponent are high (see the wholly dishonest attacks on John Kerry in 2004 by the "Swift Boat Veterans for Truth"), while voters ensure that the risks remain relatively low. … In this miasma of misinformation, Americans throw open their arms, embracing their own party’s political deceptions as the best route towards toward policies they think will benefit them. Take a look at the Facebook pages and Twitter feeds of politically engaged friends. You’ll likely come across dozens of links highlighting an egregious political lie, but good luck finding a friend who highlights whoppers from both parties. And even if political lying is unevenly distributed by ideology, as is often claimed, we could expect examples of outrageous dishonesty from their own side, just far fewer.