Mid-term elections occur in the middle of a president's term in office, hence the name mid-term. While presidential elections are held every four years in the United States, general elections for other positions are held every two years. These elections usually involve state governors, state and federal congressmen, and a number of local elected positions, such as county commissioners, city councilmen and judges. Since US senators serve 6 year terms, their re-election campaigns are usually held at this time too.
Non-presidential elections are often viewed as a litmus test for the sitting president's effectiveness as a political party's leader. A popular Democratic president, for example, may use his own popularity to bolster the campaigns of Democratic candidates during mid-term elections. An unpopular president, however, may not be able to provide much of a political boost for his party. Very close races may hinge on the public's perceptions of the Republican and Democratic parties, not necessarily on the local elections themselves.
Some mid-term elections have become legendary. When former President Clinton was elected in 1992, many political analysts saw it as an indictment against the failed economic policies of previous Republican administrations. The ruling Democratic party, buoyed by a popular president, should have swept many of the 1994 elections. Instead, a revitalized Republican party, led by Senator Newt Gingrich, managed to regain control of Congress. The 1998 elections were not quite as dramatic, but the 1994 reversal of fortune by the Republicans is still viewed as a remarkable comeback.
Mid-term elections can also be considered glimpses into the future. A sitting president seeking re-election could feel empowered if his political party gained strength during these elections. If his or her party suffered significant losses at the polls, however, then it may be a sign that changes in policies or public perception are necessary. Leaders from both political parties keep a very close eye on the election results, and use this information to formulate a winning strategy for their presidential candidates.