President Obama won re-election with the rock-solid support of what has become known as the “Obama Coalition” — young people, minorities, women, and low-income voters. Without a firm foundation — and high turnout — among those groups, Obama would not be in the White House today.

Now, little more than a year after the president’s re-election, his job approval rating has fallen among all segments of the American electorate. But it has fallen the most among those who did the most to elect him.