President Obama took to the stump this week to respond to criticisms of his health care plan. But he now confronts an even deeper problem, one that threatens not only the success of Obamacare, but his presidency itself. Since the beginning of his term, Obama's personal popularity has exceeded that of his policies--a gap that was obviously unsustainable. Yet the final resolution remained unclear: Would his personality make his policies more popular, or would his policies drag down his personal likeability?

As the health care debate unfolds, we are seeing something we could not have predicted just weeks ago. President Obama's popularity is eroding--fast.

This week the Rasmussen poll of likely voters found the president's approval rating dipping below 50% for the first time....