President Obama must explain this week why a second term would be any better than his first. That’s hard to do when his policy prescriptions haven’t changed and he has become more, not less divisive, over time.

Obama’s staffers have a day to figure out how to answer the question: Are you better off now than you were four years ago? They were stumped, surprisingly, on the Sunday talk shows. Surely someone must have thought it would come up sooner or later. Obama can blame George W. Bush or Congress or Europe or whomever he likes but if he didn’t solve the mystery of economic recovery in the past 3½ y ears — two of which enjoyed the benefit of majorities in both houses of Congress — how is he going to do so with four more years?

It would be one thing if he did a mea culpa. (“I realize we blamed too much, spent too much and vilified too much.”) But I expect absolutely no recognition that his own policies or rhetoric were faulty.

What are his super-duper specific, new ideas for jump-starting the economy? He has, from what I can tell, three: Raise taxes on upper-income taxpayers including small business, hire more teachers and have another infrastructure stimulus. The first is obviously a “fairness” gambit and by any theory of economics (Keynesian, supply-side, etc.) is counterproductive in such a weak economy. Don’t take it from me; Ask Obama circa December 2010. The other two are ludicrously puny and ill-suited to driving growth and encouraging hiring. I think Obama himself recognized that it’s hard to come up with those “shovel ready” jobs.

The logical and political dilemma at the center of the Obama campaign has never been more clear. If we are not better off than when Obama took office and there is no dramatic policy adjustment ahead, why would another term be any different? Yesterday, Republican vice presidential candidate Paul Ryan drilled down on this in a written statement: “Today’s admission by Democratic Gov. [Martin] O’Malley that Americans aren’t better off today than they were four years ago is more proof that President Obama’s policies aren’t working. President Obama’s failure of leadership has led to 42 straight months of unemployment above 8 percent, 23 million Americans struggling for work, $5 trillion in new debt and a $716 billion cut in Medicare to fund Obamacare. While Team Obama continues their campaign of fear and division, we are talking about the big issues that Americans face. That’s why we have a plan to strengthen the middle class and create 12 million jobs, protect Medicare, and cut the federal deficit so our economy can start growing again.”

The president’s second major challenge is to make the case that he can govern with divided government. Surely at least one house of Congress will be in GOP hands, so how will he be any more successful in bridging differences and gaining consensus when he could not be in the past?

He sometimes says Republicans will be chastened if they lose. Really? That doesn’t fit with the liberal narrative that Republicans are devoted to the president’s political destruction. And even if some Republicans were inclined to compromise, Obama’s mean-spirited and wholly negative campaign has put forth little of substance that could serve the basis of a mandate.

The presence of former president Bill Clinton at the Democratic National Convention will be a reminder of how a far more flexible, charming and creative Democrat wheeled and sealed, cajoled and compromised his way to success after success. Who really thinks Obama embodies those qualities?

The problem with running as a failed candidate is inescapable: If you failed before, why not give someone else a shot? In the case of Obama the problem is particularly acute since the alternative does have a starkly different approach to the economy and a track record of compromise, accomplishment and deal making. You can see why it was so essential for the Obama camp to try to destroy Romney personally.