Thursday’s list includes three former members of Congress, a dozen former high-ranking members of Republican administrations and others.
The officials played down the disparity between the number of offices they have up and running and Hillary Clinton's.
Three black Republicans will help the party and the Trump campaign attract African American voters.
The Virginia Beach congressman plans to retire at the end of his term.
"We have been dealing with the Clintons for 40 years," Arkansas Attorney General Leslie Rutledge said at a Thursday news conference. "We know about cattle futures, Troopergate, Whitewater."
Major protests begin today; police will patrol on 300 bikes.
The next three days could be the most contentious yet for the Republican Party as anti-Trump forces make a last stand.
"I feel that going against the voters will tear our party apart and only give the Democrat presumptive candidate the edge," said Rosie Tripp, a rules committee member from New Mexico.
A confederate flag defender loses and a Bernie backer wins.
Latest salvo aims to chip away at Rubio’s support among conservatives in early-voting states.