Through the years the American electorate has consistently underestimated the power of midterm elections. Only the grand quadrennial spectacle of voting for the presidency represents a greater hallmark of our democracy, a testament that the people continue to rule.

Aside from this one major responsibility, each midterm and each presidential election bear the same burden. Both elect one-third of the U.S. senators and all 435 members of the House of Representatives. Over time, voters who bypass the midterm elections participate in filling only half as many House and Senate seats as those who cast ballots every two years.

This omission should not be turned aside cavalierly. House and Senate seats represent a priceless pool from which most presidential and vice presidential candidates are nominated. Thus, a citizen who fails to vote at midterm misses an opportunity to assist in determining those who become officeholders at the highest levels of government. Midterm elections also select those who reach the first rung on the political ladder, as well as those who move up that ladder to committee seniority and chairmanships. Some too are voted off the ladder at midterm.

Since the first Dwight Eisenhower-Adlai Stevenson contest in 1952, the Democrats have chosen 10 Senators and 7 Governors as their presidential candidates. Meanwhile, the party has selected 15 Senators, 1 House member (Geraldine Ferraro), and 1 non-politico (Sargent Shriver) as vice presidential nominees.

During the same period the Republicans have drawn their candidates from a broader array of talent. For the presidency, they have named six senators, five governors, three House members (Gerald Ford and George H.W. Bush twice) and three leaders from the non-political realm (Eisenhower twice and Donald Trump). For the vice presidency, the GOP has selected six senators, four governors and seven members of the House.

Party leaders are alert to Congress being a valuable source for nominees, but these figures are not compelling enough to send Americans to the voting booth in impressive numbers.

An average of 60 percent of those eligible to participate in presidential elections perform their duty, but only 40 percent join in making midterm choices. In 70 percent of the 38 midterm elections since the Civil War, the party that gains control of the House of Representatives at midterm has dominated the presidency two years later.

Politicians look at a midterm election as a report card. Not only does it offer an evaluation of a president’s first two years, but it also registers the degree of optimism with which voters anticipate the future. A president generally loses some support at midterm, but if that loss is so deep that control of the House passes to the other party, the outlook for re-election is statistically diminished.

Over the 150 years since the Civil War, some midterm reports have been more dramatic and nation-shaping than others. Those years have produced at least five midterms with long-range results. The pre-election atmosphere surrounding this coming 2018 midterm suggests that a sixth critical election may be added to the list because of the “high stake” variables that are developing.

The first two years of the Trump administration have presented the midterm voters with a “mixed bag.” In 2016, Mr. Trump officially won the presidency handily in the Electoral College. The Democrats meanwhile received almost 3 million more popular votes — more than half of which can be counted upon to skip a midterm vote.

The president was elected, in part, to break the gridlock between conservatives (mostly Republicans) and liberals (mostly Democrats) in Congress. On that issue he achieved a modicum of success, but in foreign affairs he also enjoyed mixed results. His addresses to NATO and the United Nations were abhorred by those with a sense of diplomatic decorum. But they were endorsed by those who believe that the U.S. is overextended, financially and politically, in international alliances.

In a brusque manner, he has insulted our long-standing allies, individually and collectively, to the revulsion and applause of these same audiences. On a crucial diplomatic issue, the president achieved a coup by opening the diplomatic door to North Korea, but his “brinkmanship” technique in doing so can be admired only by the most witless.

With the assistance of Congress, the president also simplified the tax code. These and other qualities of the Trump administration will be evaluated at the polls. The voters will decide whether they want the president to push forward in his inimical manner or if they are disappointed in what they have observed. At this point, either decision can push the nation into the category of the five crucial elections identified below.

1866 Midterm Election

The Civil War validated the primacy of the central government and wiped out all thought that America was a confederation of individual states. This first postwar Congress was confronted with crucial problems and consequences.

This 1866 Congress acted decisively. Toward the South it imposed harsh terms of Reconstruction, as sarcastically stated by Pennsylvania legislator Thaddeus Stevens: “The South must learn the principles of freedom and eat the fruits of foul rebellion.” The result was a sullen South and a race problem that spread nationwide with a disturbing aftermath that lingers to the present.

Toward the North, this session resorted to the well-tested Jeffersonian maxim: The government that governs best governs least. Entrepreneurs such as John D. Rockefeller (oil), Cornelius Vanderbilt (railroads), Andrew Carnegie (steel, particularly after 1873) accumulated millions in wartime profits. This Congress’s laissez-faire attitude toward business produced the greatest industrial power in the world, as well as the world’s greatest private concentrations of wealth.

1894 Midterm Election

In the 28 years after the 1866 midterm election, the entrepreneurs, endorsed by both political parties, transformed the nation’s economic orientation from agriculture to industry. Western farmers and industrial workers were irritated by the negative gains they received from this business success. With the depression of 1893 still in their midst, this midterm session initiated a period of lasting progressive reforms.

The Democrats captured the presidency in 1892, but the Republicans gained control of Congress at midterm. Generally, such a victory is followed by the same party claiming the presidency two years later. Not only did that happen, but it also began a 36-year run of GOP control interrupted by the presidency of Woodrow Wilson.

1918 Midterm Election

In the midst of the long Republican tenure in the central government, the party split over the issue of progressive reform. Woodrow Wilson and the Democrats came to the presidency in 1912 and continued the progressive endeavors. After he pledged to keep the nation out of war, he was re-elected in 1916. Two years later the midterm election returned control of the House of Representatives to the Republicans. According to the most common pattern, that would lead to a Republican presidency in 1920 — and it did.

The GOP success in 1918 can be attributed to the U.S. entry into World War I in 1917, accompanied by the Espionage Acts that curbed individual freedoms. These wartime regulations and restrictions brought an unwanted shock to the American householder. He was urged to conserve in the use of fuel, beef and wheat. These heatless, meatless and wheatless days were known as “Hooverizing” because Herbert Hoover was the U.S. food administrator.

The vagueness of these laws prevented any widespread discussion of Wilson’s plan for collective security. In the public mind, that curtailment of expression contributed to the nation’s rejection of the League of Nations.

1930 Midterm Election

Influenced by the stock market crash of 1929, the long-term Republican grip on national politics collapsed with the 1930 midterm election. That year the Democrats began an equally long domination of the central government (1930-1966), with the Eisenhower years being the only interruption.

At the end of Election Day, 1930, Republican control of the House (1-vote margin) was tenuous because certain returns had not yet been tabulated. Indecision reigned throughout the 13-month period (from Election Day to December 1931), at which time Congress was legally scheduled to meet. An unbelievable 14 elected House members died in those intervening months and were replaced. The Democrats proved to be the healthier party, politically and physically. When Congress did assemble, their party enjoyed a 5-vote margin (219-214).

This series of deaths represented the immediate cause for the passage of the Twentieth Amendment, which changed the convening date of Congress to January 3 following an election. The same amendment shifted the presidential inauguration date from March 4 to January 20.

1966 Midterm Election

The political pattern around the midterm election of 1966 was convulsed by two pervasive issues: the Vietnam War and the Voting Rights Act of 1965. The Democrats won this election in both houses. The general rule suggests that the party winning the midterm should capture the 1968 general election. That did not occur.

By a narrow margin Richard Nixon and the Republicans gained the presidency but uncharacteristically did not carry either branch of Congress. In fact, the party did not control either the midterm in 1970 or Congress in 1972 when Nixon was re-elected.

From another angle, the 1966 midterm offered surprises. The Voting Rights Act produced mixed results for President Lyndon Johnson. This legislation stated that it was illegal to impose requirements through technicalities that would prevent African-Americans from voting in federal, state, and local elections.

Unpopular in the South, Johnson did not suffer politically elsewhere for promoting this legislation. Democratic success was also attributed to the public’s perception that Johnson was winding down the Vietnam war.

Likewise, this election offered positive signs for the Republicans. After Barry Goldwater’s crushing presidential loss in 1964, the party experienced a spectacular recovery and gained 47 House seats, which included the first, although modest, shift in the South from a Democratic to a Republican stronghold.

This 2018 midterm vote, coming more than a half century after the 1966 historic event, may hold equally provocative results. Only those voters who appear at their polling stations can participate in charting the nation’s course. How dramatic the change will be depends on you!

James A. Kehl is a professor emeritus of history at the University of Pittsburgh, where he served as dean of the College of Arts and Sciences.

First Published: November 4, 2018, 4:00 a.m.