In Tuesday’s victory, Barack Obama not only won his second term. He protected his first.The re-elected president has called for bipartisanship in addressing four ambitious priorities over the next four years: reducing the deficit, overhauling the tax code, revising immigration laws and reducing the nation’s dependence on foreign oil.Left unsaid was the reality that he also can now implement the hard-won achievements from his first four years -- the health-care law called the Affordable Care Act and the Wall Street regulatory regime known as Dodd-Frank -- which Republican rival Mitt Romney had promised to begin dismantling "on Day One” in the Oval Office."If he had lost there would have still been the legacy coming from the fact he was the first African American to have won the White House,” says Robert Dallek, one of a group of historians who has met privately at three White House dinners with Obama. "But now he can hammer into place the Affordable Care Act that would have been in jeopardy if he had lost the election. Now it will be a fixed and featured part of his presidential terms.”What’s more, Obama will be in a position to reap the advantages of governing at a time of growth, if the slow-but-steady recovery continues to gather steam -- a stark contrast to the spiraling economic crisis that greeted him when he took office in 2009.He already was a groundbreaking president, as the first person of color to win the nation’s highest office. By defeating Romney, he also joins the elite ranks of just 16 other men in history who have managed to win the White House twice."Obama was elected twice by a majority of the vote, the first Democrat since Franklin Roosevelt to do that, and he was re-elected despite extraordinary circumstances on the economy,” says Simon Rosenberg, founder and president of NDN, a Democratic-leaning think tank. That is "an affirmation of him and of the country giving him their trust to continue the agenda and finish it.”Rosenberg predicts Obama will be "very aggressive” and in the strongest political position he has been since jafter his first inauguration."He’s a better and smarter president than he was, and he’s learned a lot over the last four years,” he says.The morning after the inaugural balls on Jan. 21, he still will face a divided government, as he has since the 2010 midterm elections. While Democrats expanded control of the Senate Tuesday, Republicans maintained their majority in the House of Representatives.He’ll also face a sharply divided America. He won by a narrower margin than in 2008 -- the first second-term president in modern times who failed to carry a bigger margin when he won re-election -- and he commanded support from only about four in 10 white voters.On the other hand, Obama has forged and energized a coalition of the most rapidly growing parts of the U.S. electorate: Hispanics, African Americans and members of the young Millennial generation, plus some whites, especially highly educated women.If it holds, that coalition could give Democrats the sort of enduring majority that FDR built in his era.The opening test of Obama’s second term will come soon in negotiations with Congress to avoid falling over the "fiscal cliff” at the end of the year.Without a deal, the Bush tax cuts will expire, raising taxes on everyone, and sweeping spending cuts will go into effect at the Pentagon and across domestic programs. Some economists warn that could send the economy back into recession.Those talks will help define the fiscal possibilities of his second term and provide an early signal of whether there is going to be a ceasefire in the partisan wars."How the fiscal cliff goes will set the terms of the second term,” says Neera Tanden, a former Obama adviser who now heads the liberal-leaning Center for American Progress. "That will have an impact beyond six months.”Where’s the mandate?In this year’s campaign, Obama didn’t do much to establish a policy mandate for his victory. Instead, he and his allies focused in large part on undermining Romney, depicting him as a heartless corporate raider with little empathy for the lives of most Americans.