Late Thursday night, the Democratic National Convention came to a close. Hillary and Chelsea Clinton spoke. The balloons fell, the families took the stage, and the Rev. William Shillady gave a final prayer.

But everyone knows which image will be most remembered: that of Khizr Khan, the father of fallen Muslim U.S. soldier Capt. Humayun Khan, waving his pocket-size Constitution in the air.

In response to Donald Trump’s proposed ban on Muslim immigration, he addressed the candidate in his speech, asking, “Have you even read the United States Constitution? I will gladly lend you my copy,” while pulling the document out of his breast pocket.

Now, sales of the little book are skyrocketing. A $1 edition of the pocket Constitution printed by the nonpartisan National Center for Constitutional Studies became the second-bestselling book on Amazon. It remains there today.

It’s not just sales; Google searches for the document increased more than tenfold on Friday compared to the daily average of the previous month.

Constitution apps haven’t done nearly as well, with the most popular version in the Apple app store having only 14 reviews. Perhaps because the visual of waving an iPhone around is more reminiscent of attending a concert than a politically impactful protest.

And the ACLU is giving out the book free through Election Day, a retired tactic of the Heritage Foundation, a right-leaning think tank.

It’s tempting to view this as a partisan shift in the symbolism of the Constitution.

In recent years, pocket Constitutions seem to have been waved more on the right than on the left. They have, for instance, been a common sight at rallies for the Tea Party movement.

But earlier pocket-Constitution-waving started among Democrats. According to Slate Magazine, they were first printed in 1965, under the order of a House resolution put forth by the late Rep. Wayne Hays (D-Ohio).

Its first prominent use came, again by Democrats, following the Watergate scandal. Sen. Sam Ervin (D-N.C.), who chaired the Senate committee charged with the investigation, would pull out a pocket copy of the Constitution during hearings.

It was also famously displayed in 1998 by Sens. Carl Levin (D-Mich.) and Robert Byrd (D-W.Va.) after the Supreme Court struck down the line-item veto.

More recently, Rep. Dennis Kucinich (D-Ohio) took his out at a 2007 Democratic presidential primary debate, after no other candidate expressed support for his plan to impeach Vice President Dick Cheney for his role in beginning the Iraq War. He claimed that, by allegedly manipulating evidence of weapons of mass destruction in Iraq, Cheney “has violated this Constitution.”

And today, it seems the pocket Constitution is a weapon wielded by both sides. Even before Khan’s speech, the ACLU sold them on its website. As does the Cato Institute, a libertarian think tank. The Heritage Foundation now has them for sale in Spanish. Every House and Senate member of both parties is issued one.

It’s fair to say the two sides tend to focus on different sections of the document; Khan and the ACLU are largely concerned with the equal protection guarantee by the 14th amendment, while conservatives focus more on states’ rights, particularly the 10th Amendment and individual liberties, these days particularly the Second Amendment.

But in the wake of Khan’s stirring speech, and with rapidly rising sales, it may perhaps become universal.

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