WASHINGTON ― Republican presidential nominee Donald Trump is no fan of gun control. He said in Wednesday’s debate that Chicago, Illinois, is a perfect example of why it doesn’t work anyway.

“In Chicago, which has the toughest gun laws in the United States ― probably you could say by far ― they have more gun violence than any other city,” Trump said. “So we have the toughest laws, and you have tremendous gun violence.”

But Trump’s take glosses over one of the biggest sources of Chicago’s gun problems: Indiana. The state has lax gun laws, and its proximity to Chicago means people can easily bring illegal guns into the city. Very few crime guns recovered in Chicago have been found to come from federally licensed dealers. Instead, one way these weapons get into the wrong hands is via straw purchases, where one person buys a gun for a person who cannot legally purchase one.

A 2014 report from the Chicago Police Department, for example, found that 60 percent of guns recovered at crime scenes between 2009 and 2013 were originally bought outside of Illinois. Every state in the country contributed at least one gun to a Chicago crime scene. A whopping 20 percent came from Indiana.

In other words, it’s not that Chicago’s gun safety laws have failed. It’s that other states have failed to regulate their own gun sales.