Jan. 20, 2009, was an inspiring day. Barack Obama took the oath of office and argued that America was in a crisis caused by “our collective failure to make hard choices and prepare the nation for a new age.”

It was time, he said, to end the false choices between the orthodox left and the orthodox right. He called for “an end to the petty grievances and false promises, the recriminations and worn-out dogmas that for far too long have strangled our politics. ... In the words of Scripture, the time has come to set aside childish things.”

Obama acknowledged that some people questioned the scale of his ambitions, the scope of his grand plans. But, he continued, “What the cynics fail to understand is that the ground has shifted beneath them, that the stale political arguments that have consumed us for so long no longer apply.”

In some ways, President Obama has lived up to the promise of that day. In office, he has generally behaved with integrity and in a way befitting a man with his admirable character. Sure, he has sometimes stooped to the cynical maneuver. Contemptuous of his opponents, he has given himself permission to do the nasty and negative thing. But politics is a rough business and nobody comes out unsullied.

In moral terms, he hasn’t let us down. If he’s re-elected, his administration would probably remain scandal-free. Given the history of second terms, that is no small thing.

Moreover, Obama has been a prudent leader. He’s made no rash or disastrous decisions. He’s never acted out of some impetuous passion. His policies toward, say, China, Europe and Iran have had a sense of sober balance. If re-elected, he would probably commit no major blunders, which also is no small thing.

But the scope of Obama’s vision has contracted over the years. It has contracted politically. Four years ago, Obama won over many conservatives and independents. But he’s championed mostly conventional Democratic policies and is now mostly relying on members of his own party.

It has contracted managerially. Four years ago, Obama went to the White House with a Team of Rivals — big figures with big voices. Now the circle of trust is much smaller and political.

The mood has contracted. The atmosphere of expansive hope has often given way to a mood of aggrieved annoyance. He seems cagier, more hemmed in by the perceived limitations of his office. The man who ran on hope four years ago is now running one of the most negative campaigns in history, aimed at disqualifying his opponent.

Most of all, the vision has contracted. The arguments he made in his inaugural address were profoundly true. We are in the middle of an economic transition, a bit like the 1890s, with widening inequality, a corrupt and broken political system, an unsustainable welfare state, a dangerous level of family breakdown and broken social mobility.

The financial crisis exposed foundational problems and meant that we were going to have to live with a long period of slow growth, as the history of financial crises makes clear.

If Obama had governed in a way truer to his inauguration, he would have used this winter of recuperation to address the country’s structural weaknesses. He would have said: Look, we’re not going to have booming growth soon, but we will use this period to lay the groundwork for a generation of prosperity — with plans to reform the tax code, get our long-term entitlement burdens under control, get our political system working, shift government resources from the affluent elderly to struggling young families and future growth.

When people say they wish Obama had embraced the Simpson-Bowles deficit-reduction plan, they don’t mean the specific details of that proposal. They mean the largeness that Obama’s inauguration promised and the Simpson-Bowles moment afforded. They mean confronting the hard choices, instead of promising more bounty for everyone with no sacrifice ever.

But the president got sucked in by short-term things — the allure of managing the business cycle so that the economy would boom by re-election time. Instead of taking the midterm defeat as a sign he should move to the center, or confound the political categories, he seems to have hunkered down and become more political. Washington dysfunction now looks worse than ever.

Sure, House Republicans have been intransigent, but Obama could have isolated them, building a governing center-left majority with an unorthodox agenda. Instead he’s comforted the Democratic base and disappointed sympathizers who are not in it.

One final thing. No one is fair to President Obama. People grade him against tougher standards than any other politician. But his innate ability justifies that high standard. These are the standards he properly set for himself. If re-elected, he’d be free from politics. It’d be interesting to see if he returns to his earlier largeness.