Barack Obama, the 44th president of the United States, was elected to a second term Tuesday, defeating Republican Mitt Romney by pledging to safeguard middle-class economic interests and by reassembling the same political coalition that boosted him to victory four years ago.

Obama, the nation's first African American president, appeared to score a decisive victory, capturing most of the nine states that had been contested all year.

Romney, a former Massachusetts governor, built his campaign around the single contention that the U.S. economy is battered and adrift because of Obama's failures, and that his business experience uniquely qualified him to fix it.