Standing next to Russian President Vladimir Putin, President Donald Trump, arguing that he ran a “clean campaign” to victory, appeared to be confused about how he actually won the presidential election in 2016: because of the Electoral College.

“The Democrats lost an election, which, frankly, they should have been able to win, because the Electoral College is much more advantageous for Democrats, as you know, than it is to Republicans,” Trump said in the press conference with Putin.

To be clear, Trump only won the presidential election in 2016 because the Electoral College played to his favor. He lost the popular vote to Democrat Hillary Clinton by nearly 2.9 million votes — the biggest margin in history for a losing candidate — but won the Electoral College by 74 votes. And Democrats have lost two of the past five presidential elections because of the Electoral College. In 2000, Democrat Al Gore won half a million more votes than George W. Bush nationwide, but lost the presidency after conceding Florida to Bush by only 537 votes.

There’s a reason Trump claims the Electoral College is favorable to Democrats and not Republicans: Republicans contend that because states considered “safely Democratic” are bigger than deep-red states, they therefore have more Electoral College votes to start with.

“The Republican candidate must nearly run the table on the battleground states in order to squeak into the White House, whereas the Democratic candidate has multiple pathways to victory,” Matt Mayer, a conservative writer, explained in the Washington Examiner. Here’s how he breaks down the math:

The Democrat will almost always win the following states: California, Connecticut, the District of Columbia, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New York, Oregon, Pennsylvania, Rhode Island, Vermont, Washington, and Wisconsin... The Republican will almost always win Alabama, Alaska, Arizona, Arkansas, Georgia, Idaho, Kansas, Kentucky, Louisiana, Mississippi, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, West Virginia, and Wyoming. Those states give the Republican a base of 170 electoral votes. This electoral vote allocation leaves the Democrat just 28 electoral votes from The White House, while the Republican needs an additional 100 electoral votes to win.

But as Vox’s Andrew Prokop explained, who has the advantage in the Electoral College is not so clear-cut. There are several reasons the system isn’t fair to either Democrats or Republicans.

For one, there’s the way the Electoral College disproportionately props up smaller states by guaranteeing every state at least three electors (the combination of their representation in the House and Senate). In other words, 4 percent of the United States’ population in the country’s smallest states gets 8 percent of the Electoral College.

There’s also more weight on votes in swing states. Prokop writes:

Millions of votes in safe states end up being “wasted,” at least in terms of the presidential race, because it makes no difference whether Clinton wins California by 4 million votes, 400,000 votes, or 40 votes — in any scenario, she gets its 55 electors. Meanwhile, states like Florida and Ohio get the power to tip the outcome just because they happen to be closely divided politically.

That’s how Trump got elected: He lost the popular vote dramatically but was able to win the election because he clinched narrow wins in Wisconsin, Michigan, and Pennsylvania.

In fact, the case for keeping the Electoral College often comes from those in small states and in rural, typically more Republican, regions who don’t want small towns and rural voices to get drowned out by people who live in cities.

Either way, if you ask Trump, he falsely says he won both the popular vote and the Electoral College.