House Speaker Nancy Pelosi sports Mace of the Republic brooch during impeachment proceeding

Savannah Behrmann | USA TODAY

Show Caption Hide Caption Nancy Pelosi gives stern glare after announcing Trump impeachment Speaker of the House Nancy Pelosi gave a stern glare to some Democrats for cheering after Pelosi announced President Donald Trump had been impeached.

WASHINGTON – House Speaker Nancy Pelosi sent a deliberate message Wednesday during the impeachment debate against President Donald Trump; not just by her words, but through a seemingly deliberate fashion statement.

Pelosi wore a large, golden Mace of the Republic brooch, which is a historic symbol of the legislative authority of the House of Representatives. The pin rested atop her all-black outfit.

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Used originally as a weapon in the Middle Ages, the mace was adopted by the U.S. as a symbol of authority for the Sergeant of Arms of the House in 1789. The resolution of the symbol specified that “a proper symbol of office shall be provided for the Sergeant at Arms, of such form and device as the Speaker shall direct” and has since been used in a procession by the sergeant-at-arms for daily sessions of the House.

The sergeant-at-arms may use the mace to regain decorum on the House floor if needed.

The symbol of the mace has been noted as one of the U.S. government's most important historical symbols: an eagle with its wings spread wide seated on top of a globe that bestrides a bundle of 13 rods, representative of the original 13 states.

Pelosi has worn the mace brooch before, including when she and House Intelligence Committee Chairman Adam Schiff held a press conference to announce the impeachment inquiry.

She also sported the golden brooch during Trump's State of the Union address in February, where Pelosi stood and clapped at the commander-in-chief with a grin that caught people's attention and quickly went viral.

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"But we must reject the politics of revenge, resistance and retribution – and embrace the boundless potential of cooperation, compromise and the common good," Trump said prior to Pelosi's clap during his State of the Union address.

The brooch was a gift that several former lawmakers presented to her around the time of the address, Pelosi's spokesman, Drew Hammill told USA TODAY at the time.

“Our founders’ vision of a republic is under threat from actions from the White House,” Pelosi said Wednesday during her opening remarks. “That is why today, as speaker of the House, I solemnly and sadly open the debate on the impeachment of the president of the United States. If we do not act now, we would be derelict in our duty.”

Contributing: Ryan W. Miller, Ledyard King