Ron Brownstein: “At 250 years, America’s (fault) lines are showing. Partisan and regional divisions now rival the most intense internal conflicts apart from the Civil War.”“The escalating tension between the red and blue political coalitions is permeating almost every aspect of American life, particularly under the pile-driver pressure of Donald Trump’s polarizing and norm-breaking presidency. Even the commemoration of this momentous anniversary has split the country into the familiar antagonistic camps.”“Conflict within a nation is a difficult concept to quantify, but many measures — the widening policy differences among the states; Trump’s relentless confrontations with Democratic political leaders; the virtual disappearance of bipartisan cooperation in Congress; an uptick in political violence — suggest the US is operating at the high end of the scale.”