In the United States, divided government describes a situation in which one party controls the executive branch while another party controls one or both houses of the legislative branch. Divided government is seen by different groups as a benefit or as an undesirable product of the model of governance used in the U.S. political system. Under said model, known as the separation of powers, the state is divided into different branches. Each branch has separate and independent powers and areas of responsibility so that the powers of one branch are not in conflict with the powers associated with the others. However, the degree to which the president of the United States has control of Congress often determines his political strength - such as the ability to pass sponsored legislation, ratify treaties, and have Cabinet members and judges approved. The model can be contrasted with the fusion of powers in a parliamentary system where the executive and legislature are unified. Those in favor of divided government believe that such separations encourage more policing of those in power by the opposition, as well as limiting spending and the expansion of undesirable laws. Opponents, however, argue that divided governments become lethargic, leading to many gridlocks. In the late 1980s, Terry M. Moe, a professor of political science at Stanford University, examined the issue. He concluded that divided governments lead to compromise which can be seen as beneficial, but he also noticed that divided governments subvert performance and politicize the decisions of executive agencies. Early in the 20th century, divided government was rare, but since the 1970s it has become increasingly common.
Party control of legislative and executive branches since 1861
*The 2000 election resulted in a 50–50 tie in the Senate, and the Constitution gives tie-breaking power to the vice president. The vice president was Democrat Al Gore from January 3, 2001 until the inauguration of Republican Richard Cheney on January 20. Then on May 24, Republican Senator Jim Jeffords of Vermont left the Republican Party to caucus with the Democrats as an independent, resulting in another shift of control.
Presidential impact
Many presidents' elections produced what is known as a coattail effect, in which the success of a presidential candidate also leads to electoral success for other members of his or her party. In fact, all newly elected presidents except Zachary Taylor, Richard Nixon, and George H. W. Bush were accompanied by control of at least one house of Congress.
Presidents by congressional control and terms won/served