U.S. President Barack Obama has won a second term in the White House. His victory was narrow, but it was definitive. Equally important for him, his Democratic Party retained control of the U.S. Senate. On the other hand, as expected, the Republican Party maintained its majority in the House of Representatives.

The results mean that divided government continues in Washington. Mr. Obama has been vindicated, but the president faces the same problem he encountered in the last two years: a Republican Party that believes in no-holds-barred opposition.

It was a convincing victory for Mr. Obama, who prevailed in both the popular vote and the electoral count. There was some concern that he would win the latter while Republican candidate Mr. Mitt Romney would take the popular count, which, while not unprecedented, would have fed a Republican Party narrative that the president lacked a mandate and that his second term was flawed or somehow illegitimate.