For all the hyperventilation on the left about Mr. Obama’s rush to the center — some warranted, some not — what’s more alarming is how small-bore and defensive his campaign has become. Whether he’s reaffirming his long-held belief in faith-based programs or fudging his core convictions about government snooping, he is drifting away from the leadership he promised and into the focus-group-tested calculation patented by Mark Penn in his disastrous campaign for Hillary Clinton.