There’s little in the world more majestic than seeing this great democracy take executive power from one party and hand it to another without bloodshed or tanks in the streets.

The founders built peaceful revolutions into America’s constitutional order, and such a revolution has just bestowed the mantle of the presidency on Barack Obama.

American voters on Tuesday also left Democrats poised to dominate Congress. Obama today can claim a mandate to take the nation on a new course.

What course? The answer will be clear to the partisan Democrats who see Tuesday’s returns as the electorate’s endorsement of the full sweep of their policy goals.

It is all too easy to imagine House Speaker Nancy Pelosi and Senate Majority Leader Harry Reid pulling out the wish lists of the Democratic Party’s various constituencies. Protectionist trade restrictions, for example, or a reckless withdrawal from Iraq that forfeits the hard-won gains in that country.

That way lies hubris.

Tuesday’s election was not a wholehearted embrace of the liberal Democratic agenda; it was a repudiation of the Bush administration – which is not the same thing.

Americans know what they don’t want: more of the same, which how Obama successfully depicted John McCain. They don’t want whatever combination of greed, malfeasance and official negligence led to the near-collapse of Wall Street. They don’t want leaders who could sacrifice four years and 4,000 American lives to a failed strategy in Iraq. They don’t want ineptitude.

America took an audacious leap of faith in electing Obama, a man with a slim political resume and only four years in the U.S. Senate. His masterful presidential campaign, intelligence, calm and generous temperament – above all, his great power to inspire – made that leap seem justified.

Voters saw a candidate who spoke often of bipartisanship, healing and conciliation. The more America sees of that large man – and the less it sees of the shrill partisanship of Pelosi and Reid – the more likely Obama will succeed as president.

Obama himself must be acutely aware that new presidents have typically seen their parties lose seats in Congress two years into their first terms. Bill Clinton’s presidency was crippled when the Democrats lost Congress in 1994.

Obama’s challenge is to summon his own better angels and persuade an already unpopular Democratic Congress to do likewise. Democrats today are talking of a grand realignment that has secured their grip on power. More humility would be in order until after the 2010 elections.

Obama – and McCain, to his credit – avoided making race an issue in this contest. Nevertheless, the election of the nation’s first African-American president is paradigm-shattering event.

Until Obama began winning primaries last winter, many had underestimated how far America had come from the institutional racism of its past. Now it has become the first major nation outside Africa to elect a black man to its highest office. That can’t help but change widely held stereotypes of the United States.

However Americans may have voted Tuesday, this is a day for the nation to salute its new chief executive and wish him success. Obama has inherited immense problems. May he be equal to them.