Former President Donald Trump reportedly wants to form a new political party. For the first time in my sentient life, I say: Proceed, Mr. Trump. As he may or may not know, what he would almost certainly accomplish is to ensure that Democrats held the White House and the House of Representatives for as long as his party existed.
As many Americans already know, third parties don’t really work in the United States. Mr. Trump’s effort brings most readily to mind Theodore Roosevelt’s effort to seek the presidency in 1912 under the banner of his newly formed Progressive Party, better known to us as the Bull Moose Party. Roosevelt was furious with his protégé and successor, President William Howard Taft, who had strayed from Roosevelt’s reform agenda. He and his people formed their party — and split the Republican vote enough that Democrat Woodrow Wilson won the White House with about 42 percent of the vote.
So people know they don’t work, but not many people know exactly why they don’t work. At bottom, it has to do with the way we elect our House of Representatives. We use a system variously called winner-take-all, single-member district or first-past-the-post. It means that states are divided into congressional districts, and each district is represented by one person.
To Americans, this seems as natural as the sun rising in the east. But other countries do things differently. According to the nonprofit group Fair Vote, 90 democratic countries use multi-member districts, 54 use single-member districts like ours and 38 use a hybrid.
Maurice Duverger, a French political scientist of the mid-20th century, gave the best explanation for why this matters. In 1951, he wrote an enormous book called “Political Parties,” in which he surveyed political parties across the world (including those in Communist countries). Out of that work emerged Duverger’s Law, which holds that single-member districts tend to produce two-party systems. Duverger wrote that “of all the hypotheses” in his book, this one “approaches the most nearly perhaps to a true sociological law.”
Let’s say six candidates representing six different parties are running in a winner-take-all legislative district. Parties A, C and E are on the left, and parties B, D and F are on the right. Let’s say candidates from A and B lead the way, while candidates from C and D trail somewhat, and candidates from E and F lag behind badly.
After a couple of elections in which their candidates finish dead last, the party leaders from E and F will realize they can’t win. They’ll go to the party leaders of A and B and say something like: Look, we disagree on some things, but if you adopt X from our platform, we’ll throw our support to you, because at least we have in common that we hate the other guy.
So E and F will disappear. In time, C and D will come to the same conclusion and cut the same deal. The single-member district will have winnowed six down to two. This doesn’t happen in proportional representation systems, where all six parties can get seats in proportion to their share of the vote. But it does happen in winner-take-all systems like ours.
We’ve had third parties over the years, and sometimes, at moments of great instability like the 1850s, fourth and fifth and sixth parties. But they don’t last. The reason for that is the remorseless logic and inevitable direction of Duverger’s Law. Let’s say Mr. Trump’s Patriot Party — or whatever he calls it, since there might be legal issues with that name — runs congressional candidates in certain targeted districts. And the party wins, say, 17 seats. Pretty good, for a new party.
But given that Trumpy candidates aren’t likely to do very well in blue or even most purple districts, the net effect is probably going to be that they’ll be unseating 17 Republicans. And what’s the effect of that? To ensure that the Democrats — the radical left socialists! — hold a House majority.
Likewise, let’s imagine the Patriot Party running a presidential candidate, most likely Mr. Trump himself, while the Republicans and Democrats run their candidates. Mr. Trump will get a lot of votes. He may even beat the Republican, as indeed Roosevelt bested Taft in 1912. But he will split the center-right vote in two, while the Democrat will get a typical 48 or so percent. Result? The Democrat will carry a lot of states with a plurality and thus win the Electoral College. And in the long run, the inexorable machinery of Duverger’s Law will ensure that the Patriot Party is folded back into the Republican Party.
If Mr. Trump were serious about building a third party, one real approach would be to mount a campaign to do away with single-member districts. Our method of electing Congress isn’t in the Constitution. It’s a matter of law. For our first five or six decades, a number of states elected all their members of Congress on an at-large basis. So Congress can change the law if it wants to — but members of Congress are loath to change laws that might affect their own employment.
One should never say never on these matters. The Whigs split in the early 1850s when their internal divisions over slavery became unbridgeable, which helped lead to that decade’s multiparty mayhem. That “mayhem” led to the rise of a new two-party system and, in 1860, elected the savior of the Republic. So it has happened. Most recently, about 165 years ago. (The Bull Moose Party, by the way, fizzled out in six years.)
But Mr. Trump would basically be creating a party that would make Democratic dominance much more likely.
He probably doesn’t know all this. Or maybe he does, and still wants to do it. If the latter, it would be what the Republicans so richly deserve for embracing someone who wasn’t really one of them to begin with and who practically has shaken our democracy to its core with their acquiescence.