THE miracle ended at the first debate, in Denver, and the problem with that face-off went beyond Obama’s sleepwalking to the kinds of subsequent debates it forced on him. To shake off what happened, he had to turn truculent, and while that technically “won” him his second and third meetings with Romney, he lost something in the bargain. He undercut his high-minded, big-vision brand, whole stanzas of doggerel intruding on the poetry.

His “bayonets” line was clever all right, and plenty fair in its way, but it had a schoolyard nastiness to it, the same nastiness in one of his campaign’s most prominent ads, which showcases Romney’s off-key rendition of “America the Beautiful.” I wonder how that line, that ad and the overall atmospherics register with voters in the middle, some of whom are no doubt asking themselves where “hope and change” went and hid.

The main cause for this contest’s closeness is arguably Obama — and the ways in which he has disappointed, confused and alienated some of the voters who warmed and even thrilled to him four years ago. During his first term, he at times misjudged and mishandled his Republican opposition. As a communicator, he repeatedly failed to sell his policies clearly and forcefully enough.

His tone is markedly changed from 2008, a tactical decision that may not be the right one.