The history of the United States from 1991 to 2008 began after the fall of the Soviet Union which signaled the end of the Cold War and left the U.S. unchallenged as the world's sole superpower. The U.S. took a leading role in military involvement in the Middle East. The U.S. expelled an Iraqi invasion force from Kuwait, a Middle Eastern ally of the U.S., in the Persian Gulf War. On the domestic front, the Democrats won a return to the White House with the election of Bill Clinton in 1992. In the 1994 midterm election, the Republicans won control of Congress for the first time in 40 years. Strife between Clinton and the Republicans in Congress initially resulted in a federal government shutdown following a budget crisis, but later they worked together to pass welfare reform, the Children's