New American President Barrack Obama and his family

Long lines greeted voters on Election Day in many key states but no major breakdowns or irregularities were reported as at least 130 million Americans were expected to cast votes on a successor to the unpopular Bush.

The voting on Tuesday capped an extraordinary two-year campaign marked by the rapid rise from obscurity of Obama and his bitter Democratic primary battle with New York Sen. Hillary Clinton, and McCain's comeback from the political scrap heap to win the Republican nomination.

Obama hammered his favorite theme throughout the campaign, accusing McCain of representing a third term for Bush's policies and being out of touch on the economy.

McCain, whose campaign attacked Obama as a socialist and accused him of being a "pal" with terrorists, portrayed him as a tax-raising liberal.

But in a difficult political environment for Republicans, McCain struggled to separate himself from Bush. Exit polls showed three out of every four voters thought the United States was on the wrong track.

In the fight for Congress, Democrats were making big gains as well, but appeared unlikely to pick up the nine Senate seats to reach a 60-seat majority that would give them the muscle to defeat Republican procedural hurdles.

Democrats had picked up four seats early on Tuesday and knocked off two-high profile Republican incumbents — North Carolina Sen. Elizabeth Dole, a former presidential candidate and wife of 1996 Republican presidential nominee Bob Dole, and New Hampshire Sen. John Sununu.

Democrats also gained about 25 more House of Representatives seats to give them a commanding majority in that chamber.