Donald Trump’s election with fewer popular votes than Hillary Clinton has raised again the question of why the presidency is decided through an Electoral College and not a popular vote. Mr. Trump himself said in a recent interview said that a popular vote seems more sensible.

Many people who are currently calling for the abolition of the Electoral College, however, don’t realize the chaos that would result.

Two elements of the “Great Compromise” among the large and small states led to the ratification of the Constitution. A House of Representatives would reflect the popular vote—disadvantaging the small states—but a Senate would give the small states equal representation with the large ones.

This idea was carried through to the Electoral College, where each state’s allocation of electoral votes is simply the total of its representation in the House and Senate. This again gave the smaller states some additional power in the important choice of the president.

Leaving aside the fact that a deal is a deal, there are very practical reasons why we will always need the Electoral College under our current constitutional system.

The most important is that we want the presidential election to settle the question of legitimacy—who is entitled carry on the office of the president. Under the Constitution, the person who receives the most electoral votes becomes the president, even if he or she does not receive either a plurality or a majority of the popular vote.

In the election of 1992, Bill Clinton received a majority of electoral votes and was the duly elected president, despite the fact that he received only a plurality (43 percent) of the popular votes. A third party candidate, Ross Perot, received almost 19 percent. In fact, Bill Clinton did not win a majority of the popular vote in either of his elections, yet there was never any doubt—because he won an Electoral College majority—that he had the legitimacy to speak for the American people.

This points to the reason why the Electoral College should remain as an important element of our governmental structure. If we had a pure popular vote system, as many people who are disappointed with the 2016 outcome are now proposing, it would not be feasible—because of third party candidates—to ensure that any candidate would win a popular majority. Even in 2016, for example, although Hillary Clinton won the popular vote, she only received a plurality (48 percent)—not a majority; third party candidates took the rest.

If we abandoned the Electoral College, and adopted a system in which a person could win the presidency with only a plurality of the popular votes we would be swamped with candidates. Every group with an ideological or major policy interest would field a candidate, hoping that their candidate would win a plurality and become the president.

There would candidates of the pro-life and pro-choice parties; free trade and anti-trade parties; pro-immigration and anti-immigration parties; and parties favoring or opposing gun control—just to use the hot issues of today as examples.

We see this effect in parliamentary systems, where the party with the most votes after an election has to put together a coalition of many parties in order to create a governing majority in the Parliament. Unless we were to scrap the constitutional system we have today and adopt a parliamentary structure, we could easily end up with a president elected with only 20 percent-25 percent of the vote.

Of course, we could graft a run-off system onto our Constitution; the two top candidates in, say, a 10-person race, would then run against one another for the presidency. But that could easily mean that the American people would have a choice between a candidate of the pro-choice party and a candidate of the pro-gun party. If you thought the choice was bad this year, it could be far worse.

Those who complain now that it is unfair for Donald Trump to become president when he received fewer votes than Hillary Clinton have not considered either the implications of what they are proposing or the genius of the Framers.