Having made history, Barack Obama now must make policy. Having achieved power, he now must use it. Having spoken the poetry of campaigning, he now must master the prose of governing. Having become a symbol, he now must demonstrate results. Having stoked hope, he now must redeem it.

Few presidents in American history have come to office with such promise and faced such challenge. Abraham Lincoln had the challenge without the apparent promise; the country was riven with moral divisions, the Union was shattering, the government had almost no army, and the rebel nation had all the smart generals. Gerald R. Ford faced a crisis of confidence that shook the Constitution and faced the curse of inflation, but for him the very act of taking office calmed the country. Franklin Roosevelt had one big problem, the Great Depression, not to be underestimated, but only one.

Obama’s challenges

When Sen. Obama becomes President Obama, he will face four challenges, each one big enough to daunt a president of uncertain faith. There is the economy, which helped propel Obama to office. There are two wars, which unsettled the nation for the past several years. And there is the threat, unrealized but not unrealistic, that underground ideological enemies of the United States still are determined to attack and punish its people.

“This is a profoundly historic election,” the historian David McCullough said in a telephone conversation election night. “Barack Obama is a pivotal and transformative figure.”

But to be remembered as more than a symbol, he must produce more than symbolism. His rivals for office – first the steely smart Hillary Rodham Clinton, then the heroic John S. McCain – tried to dismiss Obama as a man of mere words. He prevailed over both. Thus far his achievement is formidable: breaking an ancient barrier and giving 21st-century breath to the 18th-century preamble of the Declaration of Independence.

But in truth, he has won only the platform from which to achieve. Obama clearly knows this. His was a remarkable victory speech, for it drew not from previous victory speeches but from three inaugural addresses – not second- or third- or fourth-term inaugurals, but from the first-term inaugurals of FDR and Lincoln and the sole inaugural of John F. Kennedy. These are the modern presidents, along with Ronald Reagan, who tamed the English language and used it as a tool of office. Obama must do that as well.

But he must do more. He must slay the economic demons, bring Iraq to a passable version of peace, prevail in Afghanistan, remain vigilant against the silent killer disease of terrorism.

Much is expected

From one to whom much was given – in Obama’s case an inner serenity, an instinctive eloquence, the presidency itself – much is expected. It is a New Testament thought appropriated by Presidents Kennedy and George W. Bush, and it is the burden that President Obama must live with and transform into an opportunity.

His first challenge is to work out how he uses hope. It was the oxygen of his campaign, the signature emotion of his drive to the presidency.

Only a few of our presidents came to office on a platform of hope. Lincoln was not one of them; he hardly mentioned hope and, as a man who suffered from depression and worried about the vanity of human wishes, was not a natural sentinel of that sentiment. In modern times and in various degrees, Kennedy, Jimmy Carter, Reagan and Bill Clinton were symbols of hope.

Kennedy didn’t live long enough to realize his, and Carter tried but failed. Reagan succeeded, with the help of an arms buildup that eventually helped lead to the crumbling of communism. Despite his difficulties, Clinton maintained and spawned a sunny hopefulness that nurtured a national sense of inclusiveness – an inclusiveness that helped lead to Obama’s election last week.

The new president must also tend to a new constituency in American politics: the young voters who flocked to his cause and then, defying their elders’ expectations, flocked to the polls as well, providing him with a surge of his own.

An important element of Campaign 2008: At least 2.2 million more young voters (aged 18 to 29) came to the polls than in 2004, representing about one-sixth of the votes cast.

Morley Winograd and Michael D. Hais, the leading experts on the millennial generation, believe that most of the members of the new generation who were eligible to vote actually cast a ballot in 2008. While John F. Kerry, the 2004 Democratic nominee, won 54 percent of that group’s votes, Obama took 66 percent, by far the largest margin of any age segment in the Obama column.

A ‘new day of politics’

The result is that this group has a special status in the Obama circle and perhaps a special call upon its loyalties. This introduces a significant new variable in American politics as the new administration examines such unavoidable issues as the future of Social Security – and as a new generation enters the electorate as Democrats, an affiliation that, if past patterns repeat, they are likely to retain.

“We’re entering a whole new day of politics in America,” says Simon Rosenberg, president of the liberal NDN think tank, which has studied the youth movement in American politics. He raises the possibility that Obama may substitute the weekly presidential radio addresses that began with Ronald Reagan with a weekly appearance on YouTube.

Everywhere Obama looks in January he will find points to prove, areas that need attention, threats that may become crises.

Perhaps the most dangerous are abroad, in places or from groups not well recognized nor well understood today. These places and these groups, along with NATO, the remnants of the Soviet Bloc, the rising Asian giants, the developing world and our hemispheric neighbors, will be looking beyond symbols to actions from Obama.

The presidency is always a burden. In these times, and for Obama, it also bears the burden of proof.