‘1870’ buttons. Crayons. Ribbons. Lawmakers wore a variety of pins at the State of the Union. Here’s what they represent.

Members of the Congressional Black Caucus, including Representative Ayanna Pressley, and other Democrats wore a black button with the year “1870″ on it to protest police brutality.

“In 1870, a Philadelphia police officer killed Henry Truman, an unarmed Black man. The officer chased Mr. Truman into an alley, and when Mr. Truman asked what he had done wrong, the officer shot him,” Representative Bonnie Watson Coleman of New Jersey said in a video posted to Twitter. “One hundred and fifty-three years later, the Black community is still waiting for justice.”

“Last month,” she continued, “history repeated itself.”

“From Henry Truman to Breonna Taylor, the murder of Tyre Nichols echoes countless other police killings of unarmed Black Americans,” she said. “I mourn each and every life that has been stolen from us.”

Families of Black people killed by police attended the State of the Union as guests.

Coleman told the Washington Post that her intention with the pins was to “start a conversation” by highlighting the lack of progress that has been made with police reform — and to demand change.

Several dozen Democrats, among them Senator Elizabeth Warren and Representatives Katherine Clark and Pressley, were seen wearing crayon pins to signal their support for the federal government to invest in child care. Some lawmakers also brought child care workers, parents, or others affected by the child care crisis as guests on Tuesday evening.

Senator Patty Murray of Washington explained what the pin symbolized before the speech.

“Did you see the crayon I’m wearing to #SOTU today? Great — now that I have your attention, I want to talk about how child care is a serious and urgent economic crisis,” tweeted Murray, a former preschool teacher.

“Child care has to be a top priority this Congress.”

After Russian President Vladimir Putin launched an invasion on Ukraine last year, several lawmakers wore blue and yellow outfits and accessories to the State of the Union to show support for Ukraine. The country’s flag features blue and yellow stripes.

Many lawmakers again wore the colors, or sported ribbons representing the flag, on Tuesday night. Representative Mike Quigley of Illinois highlighted the pin in a tweet, saying it “show[s] our ongoing support for the Ukrainian people.”

Senate Minority Leader Mitch McConnell wore a blue and yellow striped tie.

Senator Ed Markey tweeted that he was wearing a pin from Planned Parenthood at the address.

“Abortion is essential healthcare and we need to codify this right,” he said.

Following the Supreme Court overturning Roe v. Wade, President Biden vowed that he would veto a national ban on abortion if Congress passed one.

Representative Maxwell Frost of Florida, the youngest lawmaker in Congress and first member of Gen Z to win a seat, wore a March for Our Lives pin to the address. The student-led organization fights for “bold, comprehensive policies to prevent gun violence,” according to its official website.

“Wearing my @AMarch4OurLives pin to represent the fight to #EndGunViolence!” Frost tweeted.

Controversy erupted earlier this week when several Republican members of Congress were spotted donning pins shaped like tiny AR-15s, apparently meant to show their commitment to the Second Amendment.

They were distributed by Representative Andrew Clyde of Georgia, and lawmakers including Representative George Santos of New York were among those seen wearing the gun pins. It is not clear whether the pin was worn by anyone at the State of the Union address.

Shannon Larson can be reached at shannon.larson@globe.com. Follow her @shannonlarson98.