Divided government in the United States is caused by elections resulting in one political party controlling the White House while an opposing party controls either one or both houses of Congress. This can often occur during mid-term elections where only Congressional members are up for re-election.
There is a divided government in the United States as of April 2015. This divided government should last until at least 2017, which is the next election cycle. Democratic President Barack Obama and Vice President Joe Biden control the White House, while both the House of Representatives and the Senate have a Republican majority.
Throughout history there have been a number of terms that resulted in a divided government. The first occurred from 1911 through 1913, when the Republican party controlled the White House and the Senate but the Democratic party had control of the House of Representatives. The next divided government did not occur until 1919, when a Democrat held the White House while the Republican party controlled both houses of Congress.
More recent examples of divided government include the last six years of President Bill Clinton's term from 1995 until 2001 and the last two years of President George W. Bush's term from 2007 until 2009.