The 538-member Electoral College votes Monday for the next president of the United States.

In most election years, the vote is little more than a coronation for the popular vote winner, but this year is somewhat different, as Donald Trump pulled off an unlikely victory despite trailing in the popular vote by almost 3 million.

In the weeks since the election, some Americans have called for the reform or demise of the Electoral College, or suggested that electors break their pledge and cast ballots for Democratic nominee Hillary Clinton anyway.

Amid the talk of “faithless electors” and doing away with the Electoral College, it’s worth remembering that there’s another quirk to the system that sometimes is more consequential than any other.

Electoral votes, like the number of members in the House of Representatives, are assumed to be proportional to the population of each state — except they’re not.

The U.S. has 435 members of the House of Representatives, but 538 electoral votes. This is because each state also has two U.S. senators, and each senator represents an additional electoral vote. (The District of Columbia is also given three electoral votes.)

In other words, a sparsely populated state, such as Wyoming or North Dakota, is allowed three electoral votes when, proportionately, both would only have one. Wyoming is home to a population about 1.5 percent the size of California’s, but it gets nearly 6 percent of the number of electoral votes California gets.

This isn’t by accident. Much of the founding framework of the American system of government favors rural areas and small states, notably the two Senate votes doled out to each state, regardless of size. Since those smaller states historically go red during elections, it can be advantageous to the Republican Party in Senate elections and in the race for the White House.

In the 2016 election, Trump actually won seven of the 10 most-populous states, and Clinton won seven of the 12 least-populous. Had senators been excluded as electoral votes, the outcome would’ve been the same, with a very similar margin of electoral victory for Trump.

How would Clinton have done in the Electoral College if every state was worth their population? The same https://t.co/aO9YNM5tE7 — Nate Cohn (@Nate_Cohn) December 19, 2016

Trump won 306 electoral votes, to Clinton’s 236. By flipping big states that are typically blue, such as Michigan and Pennsylvania, Trump shook up the map. But in a slimmer electoral victory, that might not have been the case. During the 2000 presidential election between Democrat Al Gore and Republican George W. Bush, for instance, the distinction mattered. Gore would have won the presidency if only representatives — and not senators — were counted as electors.