It was the most unexpectedly powerful moment of last week’s Democratic National Convention. Standing onstage in Philadelphia, Khizr Khan pulled out his pocket-size copy of the U.S. Constitution and addressed Donald Trump by name. “In this document, look for the words liberty and equal protection of law,” said the father of a Muslim American soldier who was killed serving his country in Iraq. “Have you ever been to Arlington Cemetery? Go look at the graves of brave patriots who died defending [the] United States of America. You’ll see all faiths, genders, and ethnicities. You have sacrificed nothing and no one.”

We all know what happened next: Trump spent several days in a protracted public feud with the Khan family, attempting to smear their names and faith while many, though definitely not all, of his fellow Republicans looked on in horror, if not exactly shame. It’s hard to think of a worse look for any presidential candidate—let alone the nominee of a party known for shows of solidarity with the military—than attacking the parents of a fallen U.S soldier.

What happened at a Trump rally in Maine on Thursday may be a not-all-that-distant runner-up in terms of pure imagery, though.

Protesters standing silently with copies of the Constitution held high booed by @realDonaldTrump supporters: pic.twitter.com/9swBnvoBYn — Jeremy Diamond (@JDiamond1) August 4, 2016

To be fair, the pro-Trump crowd is clearly booing the protesters themselves, and not, you know, the actual United States Constitution. Still, in terms of is-this-really-happening symbolism, the reaction may even surpass the scene just days ago at a Nevada rally where the crowd shouted down the mother of an Air Force service member who dared question Mike Pence about Trump’s respect, or lack thereof, for those serving in the U.S. military.

The Constitution-themed stunt—and, yes, that’s what it was—was so clever because its success relied simply on the Trump-loving crowd reacting exactly how everyone expected they would. In that way, the angry Trump fans aren’t really any different than the man they were shouting to defend: easy to provoke.

Elsewhere in Slate: The Bizarre, Incomplete History of the Pocket Constitution

Read more Slate coverage of the 2016 campaign.