On last New Year’s Eve, President Obama’s job approval ratings were looking good and his personal approval ratings were even better. That’s because most Americans, including many who disagreed with him, trusted him. On this New Year’s Eve, his job approval ratings are sharply down and his personal approval numbers are even worse. That’s because a majority of Americans now say they don’t trust him.

The primary reason for the change has been his very famous 2012 campaign pledge that “If you like your present health care policy, you can keep it. Period.” Because it has always been true that that pledge could not be fulfilled, the fact-checkers at Politifact have declared it the “Lie of the Year,” an award no president wants to win — particularly when there was so much competition.

I normally approach fact-checkers’ reports with a little bit of sympathy for the checkees. Every politician, including me, says something either off the factual mark or simply stupid at one time or another. It’s part of the process of constantly being on stage. You get caught up in emotion when in the heat of battle, rely on a faulty memory when pressed for a quick answer or simply make a mistake. These embarrassing moments call for explanations, retractions and/or apologies as soon as possible. At various points in my career I have had to offer all of these.

But the “If you like it you can keep it” pledge was different than these kinds of unforced errors. The administration’s own health care experts fully understood that the law wouldn’t protect all existing plans. Nonetheless, Team Obama baked the promise that it would into the campaign’s cake as one of its key ingredients. No one in the administration should have been surprised by the uproar that ensued when the facts came out to the contrary.

What were they thinking? That it would get them safely through the campaign? Good assumption; it did. That few would care once the truth came out? Bad assumption; the number affected is in the millions. That if there were a firestorm it would die down fairly quickly? Disastrous miscalculation; indignation over the unfulfilled pledge has dominated the discussion about Obamacare throughout 2013 and significantly damaged the president’s credibility. That’s going to be a problem for him in 2014.

The whole rationale for Obamacare was that it would provide health coverage for all Americans, but current projections are that as many as 29 million Americans will still be without it. That means that President Obama will have to explain why another of his pledges will not be fulfilled.

On Jan. 1, 2013, his trust level with the American people was high enough that he probably could have done so fairly convincingly. On Jan. 1, 2014, however, not so much. Whatever he has to say about why the basic premise of his plan will fall millions short of its goal will be colored by the public’s memory of what he said to them when discussing their present health care plans. A faulty promise that worked while he was campaigning has borne bitter fruit now that he is governing.

Can he recover?

Maybe. The formula for doing so remains the same. Don’t pretend that the foul-up was just a matter of circumstance, or blame outside forces. Accept full responsibility, admit truthfully what happened, fire someone and openly retract promises that cannot be kept. Above all, sincerely apologize. If you do all that, and do it well, you may reclaim the level of trust you once enjoyed. And, oh yes, Happy New Year. You’ll need it.

Robert Bennett, former U.S. senator from Utah, is a part-time teacher, researcher and lecturer at the University of Utah's Hinckley Institute of Politics.