WASHINGTON (AP) — His second term already under way, President Barack Obama aims to set an optimistic tone when he takes the oath again to lead a divided nation seeking solutions to economic woes at home and conflict overseas. Hundreds of thousands are expected to gather on the National Mall to witness Obama’s swearing in and inaugural address today. The celebrations will extend across the nation's capital, including the traditional inaugural parade and a pair of glitzy formal balls. In his inaugural address to the crowd in Washington and millions more watching on television, Obama will urge lawmakers to find common ground when they can, and preview his second term goals, including comprehensive immigration reform, stricter gun control laws, and an end to the war in Afghanistan. "What the inauguration reminds us of is the role we have as fellow citizens in promoting a common good, even as we carry out our individual responsibilities that, the sense that there's something larger than ourselves, gives shape and meaning to our lives," Obama said, previewing his address during brief thank-you remarks to donors at a reception Sunday night. The mood surrounding Obama ‘s second inaugural is more subdued than it was four years ago, when the swearing in of the nation's first black president drew 1.8 million people to the Mall. Still, organizers were expecting up to 700,000 to attend today’s events, which would make it the largest second-term inaugural in history. The weather forecast was encouraging, to a point. High temperatures were predicted for the lower 40s during the day, with a slight chance of rain and snow showers in the afternoon and flurries later. Security was tight across Washington, with several streets near the White House and Capitol Hill closed off. Humvees and city buses were being used to block intersections.