But then Republicans collapsed under the weight of the Bush era, and Obama emerged from the election as only the fourth Democrat in history to break the 51 percent barrier, with Rooseveltian majorities in Congress and an approval rating above 70 percent. Both Obama’s campaign strategists and his former colleagues on Capitol Hill congratulated themselves on having earned a clear mandate from the voters. And suddenly the president, rather than interpreting his approval ratings as a sign that hopeful voters were waiting to hear what he had to say, seemed to proceed as if he already had the public’s enthusiastic endorsement for whatever steps he and his allies felt they needed to take.

You could have imagined, at that moment, an Oval Office address, followed by a national tour, in which the new president laid out the causes and depth of the crisis he had inherited and the measures he would take over the first 18 months of his term — short-term stimulus, long-term investment, modernization of financial regulation and the tax code — to put the country on a different course. All of these policies were probably necessary, and they were probably salable too, if Obama had seen it as one of his central responsibilities to explain how they all fit together. The president and his advisers were, to be fair, inundated with the realities of multiple crises, and so Obama forged ahead with all of these policy solutions (not to mention a massive health care plan and what amounted to the temporary nationalization of the car companies), which, absent any real marshaling of public opinion, emboldened his opponents and caught much of the country by surprise.

It was a crucial misreading of the moment, and if Obama narrowly loses, it will most likely be the moment he wishes he had back.