They are called “midterm” elections, suggesting they may be less important than the “term” elections when the president of the United States is elected. An important midterm election is coming up on Tuesday, Nov. 8.

In term elections, winning presidential candidates tend to have “coattails” that elect large numbers of their own political party to the U.S. Senate and the U.S. House of Representatives.

Midterm elections, held two years after the presidential election, tend to serve as a corrective, or equalizer, to the coattail phenomenon. In the average midterm election, the president’s political party will typically lose a substantial number of its members in the Senate and the House.

Ordinarily this is a reliable occurrence. Thus in 17 of the 19 midterm elections held between 1946 and 2018, the president’s political party suffered substantial losses. The average loss in each of those 17 midterms was 27 seats in the House of Representatives. Similar losses occurred in the Senate yet were less severe.

On those few occasions when the president’s political party does not lose seats in a midterm election, there have usually been understandable mitigating circumstances.

In midterm 1934, two years after Franklin Delano Roosevelt was elected to the White House with large numbers of Democrats elected to Congress, the Democrats actually gained seats in the House of Representatives. The reason was the popularity of Roosevelt’s New Deal program to reduce the damaging economic effects of the Great Depression of 1929.

In midterm 1998, Democratic President Bill Clinton had been damaged politically by character issues. The Republicans overplayed their hand, however, with an ill-advised attempt to impeach Clinton. The electorate reacted by adding four new Democrats to the House of Representatives rather than punishing Clinton with Democratic losses.

And in midterm 2002, Republican President George W. Bush benefited from a rush of voter support following the terrorist attack on the twin towers of the World Trade Center in New York City on September 11th. The Republicans gained eight seats in the House.

Clearly the long-time effect of midterm elections is to reduce the power of sitting presidents by reducing the numbers of their political party members in Congress. This makes it more difficult for presidents to get their plans and proposals enacted into law.

Republican President Dwight D Eisenhower, who had been reelected in a landslide in 1956, suffered notable losses to the Democrats in both the House and the Senate in the midterm election of 1958. The cause was the economic recession of 1958, the first major downturn for the U.S. economy since the end of World War II in 1945.

Another significant midterm election was 1966. Two years earlier, in 1964, Democratic President Lyndon B. Johnson defeated his Republican opponent, Barry Goldwater, by a large margin and carried large Democratic majorities into the House and Senate with him. The result was great legislative triumphs such as passing two major civil rights bills and the Medicare bill providing government-subsidized health care for senior citizens.

But the southern United States did not like the civil rights bills, and the nation was becoming divided over President Johnson’s escalation in 1965 of U.S. military participation in the Vietnam War.

The Republicans therefore scored major gains in the Senate and House of Representatives in midterm 1966, and those effective Democratic majorities in Congress from the 1964 election ceased to exist.

Republican President Richard Nixon won the 1972 presidential election by a landslide. However, the Nixon presidency became embroiled in the Watergate scandal, an unsuccessful attempt in 1972 by Republican operatives (looking to steal campaign information) to burglarize the Democratic National Committee (DNC) headquarters in the Watergate office complex in Washington, D.C.

In the 1974 midterms, thanks to the Watergate scandal, the Democrats scored impressive victories in both the Senate and House of Representatives. Supporters of U.S. involvement in the Vietnam War charged that the Democratic Party “Watergate babies” elected to Congress in 1974 voted to cut off military aid to South Vietnam and thereby enabled North Vietnam to win the war.

Republican Ronald Reagan was the big winner in the presidential election of 1980, and the GOP won majority control of the U.S. Senate for the first time in 26 years. Six years later, however, in the midterm election of 1986, the Democrats were able to regain control of the Senate.

The most recent examples of important midterm elections are those of 2010 and 2014. A popular Democratic Party president, Barack Obama, won the 2008 presidential election by a wide margin and was reelected easily in 2012. In midterm 2010 and midterm 2014, however, the Republican Party scored major gains in both houses of Congress and also in elections for state governor and the state legislatures.

Thus, twice in a row, big gains for Democratic President Barack Obama in presidential years were “taken back” by the Republicans in the ensuing midterm elections.

Most midterm elections serve as a referendum on how the incumbent president is doing, or on unusual economic or national security developments.

This current 2022 midterm election is mostly a referendum on President Joe Biden. Voters like the low unemployment rate and generally admire Biden’s strategy of working closely with NATO (North Atlantic Treaty Organization) to help Ukraine fight back against Putin’s invasion from Russia. Yet Biden’s popularity is low and, aside from his infrastructure initiative, he has not earned much praise this year.

The Supreme Court’s overturning of the Roe v. Wade abortion rights precedent diverted considerable attention away from Biden. For a while it looked as though the midterm elections might become a referendum on abortion rights rather than the Biden presidency, which would help the Democrats.

A number of pivotal elections for state governor and U.S. senator seem nearly tied as we go into the last week of campaigning. It is noticeable how few Democrats want Biden to campaign for them and how few Republicans have invited former Republican President Donald Trump to campaign in their behalf.

The result may be a split decision. Yet, there will probably be enough Republican victories to continue the traditional role of midterm elections as at least a mild rebuke to the incumbent White House administration.

We will know soon.

Tom Cronin and Bob Loevy are news columnists who regularly write about Colorado and national politics.