PRESIDENTS don’t fundamentally change personalities while in office, but different aspects of their personality arise at different times. The first two years of the Obama presidency were the audacious phase: doing many big things at once. It was audacious to promote a giant health care reform in the middle of an economic crisis. It was audacious to continue to support it even after a Republican won Ted Kennedy’s Senate seat.

But, more recently, President Barack Obama has entered his cagey phase. By saying “cagey” I don’t mean deceptive. I mean cautious, incremental, clever, manoeuvering to reduce one’s vulnerabilities. I mean balancing one’s positions so as to mollify opposing forces.

In Afghanistan, Obama increased troop levels, to please his generals, while simultaneously announcing a withdrawal date, to please his party.

On deficit reduction, Obama has often said he agrees with the Simpson-Bowles approach, while simultaneously distancing himself from the specific proposals. On tax reform, Obama has frequently said he wants to simplify the code while simultaneously proposing loopholes that make it more complex.

Obama has gotten tough on China while simultaneously getting friendly with China. He has ratcheted up the heat on Iran while simultaneously trying to restrain Israel. He has promoted new oil and gas exploration while simultaneously blocking the Keystone XL oil pipeline that would transport it.

One of the crucial moments of his presidency came in April of last year.

Usually, presidents lead by proposing a budget and everybody reacts.

But Obama decided to hang back and let Representative Paul Ryan propose a Republican budget. Then, after everybody saw the size of the cuts Ryan was proposing, Obama could come in with his less scary alternative. That is cageyness personified.

This is not a new element in Obama’s personality. He has always had a cautious, cool professional streak, and a tendency to see both sides of any issue. He often seems to adopt multiple perspectives and check his own impulses. Joe Klein, the Time magazine columnist, counted 50 on-the-one-hand-onthe- other-hand formulations in “The Audacity of Hope,” Obama’s second book.

In many ways, this serves him well.

Life is about trade-offs, and often you want a leader who tries to balance.

The cagey phase has certainly served Obama well politically. Liberals pine for the transcendent emotionalism of the 2008 campaign, but, by being incremental and reducing his exposure, he has made himself more acceptable to independents. It has also served him well in foreign policy.

Most military people would rather serve under a commander who led with a certain trumpet, but Obama’s hot-and-cold approaches to China, Russia and Iran have generally been excellent. Obama’s multifaceted, maneuvering style makes him a natural foreign policy president. But I wonder if this style will serve him well domestically, given the situation he will face if he wins re-election.

In December, a re-elected Obama would face three immediate challenges: the Bush tax cuts expire; there will be another debt-ceiling fight; mandatory spending cuts kick in. In addition, there will be an immediate need to cut federal deficits. During the recession, the government could borrow gigantic amounts without pushing up interest rates because there was so little private borrowing. But as the economy recovers and demand for private borrowing increases, then huge public deficits on top of that will push up interest rates, crowd out private investment and smother the recovery.

These big problems won’t be solved during the transition. They are too complicated. Congress will find a mechanism to delay, and the nation will embark on a major effort to do tax reform, entitlement reform and debt reduction. This grand project – reforming the basic institutions of government – will consume the first two years of the next president’s new term, no matter who is elected.

It has to get done or a debt crisis will be imminent.

Leading the country through this will require the intelligence, balance and craftiness Obama has demonstrated.

But it will also require indomitable inner conviction and an aggressive drive to push change. It will require a fearless champion who will fight all the interests that love the tax code the way it is. It will require a fervent crusader to rally the country behind shared sacrifice. It will take an impervious leader willing to spread spending cuts everywhere and offend everybody all at once.

There will have to be a clearly defined vision of what government will look like at the end.

Obama has talked vaguely about tax reform. He has acknowledged the need for entitlement reform and major deficit reduction. But he has never thrown himself All In.