More than 370 Democratic congressional aides will issue an unusual public appeal on Wednesday, imploring senators — in some cases their own bosses — to convict former President Donald J. Trump for inciting a violent “attack on our workplace” that threatened the peaceful transition of power.

In a starkly personal letter, the staff members describe ducking under office desks, barricading themselves in offices or watching as they witnessed marauding bands of rioters who “smashed” their way through the Capitol on Jan. 6. Responsibility, they argue, lies squarely with Mr. Trump and his “baseless, monthslong effort to reject votes lawfully cast by the American people.”

“As congressional employees, we don’t have a vote on whether to convict Donald J. Trump for his role in inciting the violent attack at the Capitol, but our senators do,” they wrote. “And for our sake, and the sake of the country, we ask that they vote to convict the former president and bar him from ever holding office again.”