Dick Soisson was my history teacher in high school. Well, I use the term loosely. He was the gym teacher and sports coach, so the school also gave him “history,” since they had no respect for the subject. Class time involved his reading from our textbook, following the words with his finger, so he could look up, from time to time, and not lose his place. But it was all worth a comment he made one day.

He had oddly colored hair, a lot like Donald Trump’s, wore thick-rimmed glasses, an inexpensive plaid jacket, and had lost whatever muscular physique he had when he was a jock, earlier. Frumpy, I guess I’d call him. He used the non-word, “irregardless” that drove me crazy. (“Irregardless” is a horrible bastard child of “irrespective” and “regardless.”)

Anyway, on that one day, he leaned back in his chair, ran his fingers through his hair, took off his glasses, pinched his nose where the glasses had sat, rubbed his eyes, and went off-script. . . .

He looked out at us and waved his hand, in front of himself, slowly, from left to right, and back to the left. He said, if I recall it correctly (a half-century has intervened), “you know, politics is like a pendulum. It moves one way,” moving his had to the right, “and then it moves the other,” returning his hand to the left.

It was not exactly a brilliant observation, but we usually think of day-to-day politics as more like a ping-pong game, batting that noisy ball, quickly, from one side to the other, bouncing off the table, sometimes to the floor, and taking odd, spinning hops. It’s hard to keep your eye on the ball. Chaos.

Even elections, years apart, seem that way. Elect a former actor and his kinder, gentler partner, and things go one way. Elect a younger southern boy, then a cowboy, a Black man, and then a reality TV star (who has more than 60 acting credits in movies and TV). It still feels like chaos. But take a step back. In the big picture, they’re still all within one, conservative era.

There have been major characters in American history. Then, there have been the giants. The giants don’t just push laws. They don’t just look good in print, on radio, or on TV. They change the direction of the nation. Sometimes, the world. That’s what I’ve been looking at. Which among them have made a real difference?

George Washington was certainly one. He not only led us to independence, but he also fashioned our democracy. One of his main goals was to keep us from dividing into tribes, wasting time fighting, instead of working together. That failed miserably. Yet, he was instrumental in the Founding, and did set the direction of the nation.

There were other important presidents, such as Andrew Jackson, who set up the “Spoils System,” in which the winner of an election “pays off” his supporters by giving them government jobs. But for the sake of this discussion, let’s just look at the public ethic.

About a half-century later, we were blessed with Abraham Lincoln. The modest man from Illinois is best known for ending the institution of slavery, and he did change the nation in many ways. However, he didn’t live to put into practice the words at the end of his second inaugural: “With malice toward none, with charity for all, with firmness in the right as God gives us to see the right, let us strive on to finish the work we are in, to bind up the nation’s wounds, to care for him who shall have borne the battle and for his widow and his orphan, to do all which may achieve and cherish a just and lasting peace among ourselves and with all nations.” A just and lasting peace.

If Lincoln had survived, Reconstruction would have been less harsh to former slave owners, but would probably also have meant that the nation would have honored its promise to give “forty acres and a mule” to the formerly enslaved people, allowing them to build their own wealth and, eventually, political power. We ended up with retribution to some, subjugation to others.

However, Lincoln put the Republican Party in the driver’s seat, which elected Grant, Hayes, Garfield, Arthur, Harrison, McKinley, Teddy Roosevelt, Taft, Garfield, Coolidge, and Hoover. There were only two anomalies between 1860 and 1932—Democrat Grover Cleveland and Woodrow Wilson. Taft only lost because GOP voters split between himself and Roosevelt’s third-party run on the “Bull Moose” ticket.

That gave us the next man who might have changed the world, Woodrow Wilson. He brought us through the first “World War,” and the last great pandemic. But, unfortunately, he personally succumbed to that disease, which took away his resolve to have a “just and lasting peace” after the “Great War.” While healthy, he pushed France and other nations to be reasonable in its treatment of Germany. Once struck sick, Wilson gave in to the insane settlement of the war—which caused the bitterness that led directly to Hitler and the Second World War. His League of Nations never really worked. He failed to make the Great difference.

Franklin Delano Roosevelt (FDR) made the kind of change equivalent to Washington and Lincoln. He led us through the Great Depression and World War II—and gave us the United Nations. His failing was in dying too soon. When the war ended, the US reneged on promises Roosevelt made to Stalin during the war. The American public had referred to the Soviet leader as “Uncle Joe” at the time, and most Americans don’t now realize that the USSR suffered more than any country from the war—with more than 20 million people dead. They deserved help. If Roosevelt had survived, there likely would have been no Cold War. There’s no reason we could not have had the relationship we had between Boris Yeltsin and Bill Clinton after the end of the Cold War.

However, FDR changed America, giving us Social Security and a sense that we are one nation, responsible for one another. Roosevelt started a liberal era that gave Democrats the White House in every election for up to 1968 (except for General Eisenhower, who had been courted by both parties, and might as easily have become a Democratic president).

And it was not just the presidency. The coalition that FDR built made the Democratic Party the majority party for decades. Even today, there are more registered Democrats than Republicans.

There was a major change with Richard Nixon, who ran on a “Law and Order” platform, repudiating the civil rights and anti-war movements. It was Nixon whose “Southern Strategy” split the Democratic Party, when white southern segregationists began to switch to the Republican Party. But that change was not solidified until more than a decade later.

Nixon also ran on the slogan, “bring us together again,” and he did make an effort to do so, offering programs that would appeal to one side and then the other. For instance, the Environmental Protection Agency (EPA) was founded under Nixon. It was conservative, in that it was meant to “conserve” our air and water, but was soon seen as a liberal department. Likewise, for a time, Nixon proposed a guaranteed minimum income—not unlike that which was proposed by Andrew Yang this year.

But the “liberal era” didn’t end until Ronald Reagan.

Since Ronald Reagan, the word “liberal” has been so badly trashed that Democrats have run under the “progressive” label of Teddy Roosevelt, instead. Roosevelt, himself, was a true progressive. A leftist. He wanted to break up huge corporations and fought for issues related to the Common Man. One might even say that Lincoln was “liberal,” in the sense that he wanted to be fair to both sides.

Generally speaking, the liberal ethic is that we are one people, and we should be responsible for one another, by using the power of the federal government to bring about a degree of fairness, especially trying to reduce the chasm between the wealth at the top and the poverty the bottom. Meanwhile, the Conservative ethic relies on the individual, regardless of situation. As Reagan said, “the nine most terrifying words in the English language are, “I’m from the government, and I’m here to help.” Conservatives think that those with corporate and financial power should never be limited in their actions by the government.

Ever since 1980, the country has been conservative in nature. Yes, Clinton was elected, but only because Ross Perot split the conservative vote—and later, Clinton “triangulated” to co-opt conservative issues, even taking credit for programs that were initiated and pushed by his opposition. Likewise, the novelty of having a Black president gave the White House to the Democrats, but only because the Great Recession and burnout from Middle East wars could have elected any opponent of George Bush.

In fact, the Republicans nominated an anti-Bush candidate, John McCain, who was progressive in many ways, was able to reach across the aisle, and even wanted to pick a Democrat, Joe Lieberman, as his vice-presidential partner. If Obama had not been quite so different (even in color) from Bush, it’s likely that McCain would have continued Republican control of the White House.

The gist of this story is that we had liberal domination from about 1930 to 1980, and conservative domination since 1980. The giants—Washington, Lincoln, FDR, and Reagan pushed the nation in their direction, for about a half-century, each. If Mr. Soisson’s pendulum is swinging, we should expect that a liberal era might begin with some not-yet-known leader, in about 2030.

What about Trump? He is still within the Republican/Conservative era. In the flow of history, we might say that Trump is the Republican version of Lyndon Johnson (LBJ), who made great liberal change in civil rights and programs like Medicare. But Johnson led directly to Nixon. He was the “last hurrah” of the liberal era, which finally ended with Reagan.

The far-left killed the liberal era, by demanding too much. They may, as well, extend the conservative era today, demanding a litmus test—many even rejecting the selection of “the most liberal senator,” Kamala Harris.

It’s not likely that the Never Trump movement will have the same effect as the Gene McCarthy uprising under LBJ, but it might. If Trump loses in November, there will be major retribution, especially if there are serious losses down-ballot.

If Trump wins, the Trump Party may hold together, but many traditional Republicans may give up and move increasingly to the Democratic Party. Win or lose, the fact that Trump never reaches out—just as LBJ stuck to his guns—will likely lead to a liberal era in a decade or so. That’s what Mr. Soisson might have said.