A concisely written, well-phrased, cut-to-the-chase assessment piece by The Atlantic‘s Peter Beinart explains how and why the American body politic has been moving left since Obama, and that this shift is no flight of whimsy. “In the late ’60s and ’70s, amid left-wing militancy and racial strife, a liberal era ended,” Beinart notes. “Today, amid left-wing militancy and racial strife, a liberal era is only just beginning.

“An era of liberal dominance doesn’t mean that the ideological differences between Democrats and Republicans disappear. It means that on the ideological playing field, the 50-yard line shifts further left. It means the next Republican president won’t be able to return the nation to the pre-Obama era.

“That’s what happened when Dwight Eisenhower followed Franklin D. Roosevelt and Harry Truman. Ike moderated the growth in government expansion that had begun in the 1930s, but he didn’t return American politics to the 1920s, when the GOP opposed any federal welfare state at all. He in essence ratified the New Deal.

“It’s also what happened when Bill Clinton followed Ronald Reagan and George H. W. Bush. By passing punitive anticrime laws, repealing restrictions on banks, signing NAFTA, cutting government spending to balance the budget, reforming welfare, and declaring that the ‘era of big government is over,’ Clinton acknowledged that even a Democratic president could not revive the full-throated liberalism of the 1960s and ’70s. He ratified Reaganism.

“Barack Obama sought the presidency hoping to be the Democrats’ Reagan: a president who changed America’s ideological trajectory. And he has changed it. He has pushed the political agenda as dramatically to the left as Reagan pushed it to the right, and, as under Reagan, the public has acquiesced more than it has rebelled. Reagan’s final victory came when Democrats adapted to the new political world he had made, and there is reason to believe that the next Republican president will find it necessary to make similar concessions to political reality.”