F. Scott Fitzgerald famously said that "there are no second acts in American lives." But reelected presidents are required to try anyway. What's striking is how often the second acts fail to fulfill the promise of the first.

Let that be a warning to President Obama.

Over the last century, the so-called second-term curse has bedeviled every long-serving leader. Richard M. Nixon was forced from office by the Watergate scandal, whose seeds were sown during Act One. Ronald Reagan was whacked by the arms-for-hostages scandal, which showed that he was asleep at the switch. Bill Clinton was impeached for the Lewinsky scandal, which exposed his wayward attention.

Second-term White House teams are often weary and sometimes sloppy. But all too often, the curse endures because the guy in charge foolishly interprets his reelection as a mandate for sweeping change.

Back in 1936, Franklin D. Roosevelt decided that his landslide reelection gave him license to expand the Supreme Court and pack it with ideological allies; he was thwarted by reinvigorated Republicans in Congress, and his party was thrashed in the '38 midterm elections.

Most recently, we have the example of George W. Bush. After he won reelection by three million votes, he boasted: "The people made it clear what they wanted. I earned capital in the campaign, political capital, and I intend to spend it."

He decided to spend it on a mission to privatize Social Security. But as 2005 wore on, the more he talked up privatization on the stump, the less the public liked it. He lost his mojo forever in the aftermath of Katrina and the continuing folly of Iraq.

Obama says he's hip to all this history; a couple of weeks ago, he said he was "more than familiar with all the literature about presidential overreach." But at least in the short term, he's clearly been strengthened by his November victory. The trick is to leverage the result without falling prey to hubris.

Obama won reelection by (at last count) 4.67 million votes, a far larger margin than the one Bush interpreted as a mandate in '04. Moreover, Democratic Senate candidates drew 10 million more votes nationwide than their Republican opponents, and Democratic House candidates garnered one million more votes than GOP candidates as a whole.

Obama clearly has short-term capital to spend in his budget battle with the GOP. He campaigned and won on the proposition that the rich should pay their fair share of taxes. The exit polls showed strong support for an increase in tax rates for households making more than $250,000 a year, and subsequent polls confirm the sentiment.

At least for now, Republicans on Capitol Hill are feeling the heat, as evidenced by the growing number of lawmakers who are willing to entertain Obama's demand for higher taxes on the rich - a break from the long-standing absolutist decree that there should be no new taxes on anyone, ever. Even Ann Coulter said on Fox News the other night that the GOP should cave on taxes, stunning Sean Hannity; in her words, "We lost the election, Sean!"

True enough. But if Obama is going to elude the curse, he'll need to put his win in perspective. Yes, he defeated Mitt Romney by four percentage points in the battleground states, winning nearly all of them. Yes, he assembled a nascent progressive coalition of women, professionals, young people, and minorities. But success can be ephemeral. Obama would do well to remember that, a mere seven years ago, everyone was hailing Karl Rove as a strategic genius who had driven the Democrats into indefinite exile.

Political scientist John Burke recently wrote a history of the second-term curse that was posted online by the Center for the Study of the Presidency and Congress. To kill the curse, Burke wrote, a president needs to have "a clearheaded understanding . . . of what reelection really means and what power it realistically conveys. It is most likely a vote of confidence. . . . It is also, in part, a victory in a popularity contest and/or a rejection of an opponent. As a result, it probably will not yield a policy mandate for a second term. It surely is not a license to chase ideological dreams."

Obama has the whip hand in the current budget battle, and that may give him momentum for immigration reform and other fulfilled promises. His problem, inherent in the contemporary political process, is that he has a very brief window of opportunity - at most, 18 months. Though now in disarray, Republicans will surely cease their intramural sniping and regroup for the 2014 midterms. And the day after those election results are announced - with the incumbent's party likely to have taken a beating, another facet of the second-term curse - everyone will be chattering about 2016, easing Obama further into lame-duck mode.

He could beat the traditional curse by scoring breakthroughs on climate change, job creation, education, and infrastructure repair, but that's akin to saying that a frog could defy gravity by flying. His agenda would cost a lot of money, and it's a fair bet that the usual suspects - the special-interest lobbies, the right-wing think tanks, and the conservative media-entertainment complex - will reconstitute themselves and push back with a vengeance. Elections come and go; those forces are permanent.

Obama has a shot at defying the odds, but only if he can energize his voters, involve them in governance, and enlist them to counterbalance the Republican right.

The alternative is to acknowledge the following: "Second terms are almost inevitably downhill. The tendency is for an administration to run out of steam." So said Richard Nixon shortly before he raised the curtain on Act Two.