Trump appears to be mainly running his mouth, as opposed to an actual campaign. Nearly every policy proposal he makes is incredibly mean, idiotic, was already tried with bad results, is logistically impossible due to budget constraints or all four.
His idea to deport some 12 million Mexican people fits the bill. It worked so well during the Great Depression in the 1930's when about a million people, many of them US citizens, were forced to go to Mexico. Neighborhoods and parks in Mexican barrios were blocked off and everyone inside rounded up, arrested without due process, and summarily deported. Activists, labor protesters, strike leaders and community spokespeople were particularly targeted. Entire communities became like deserted post-war zones, as the desperate family members who had not yet been arrested searched for missing relatives.
As far as I know, there has been no official apology, let along reparations to the people who lost their homes, businesses and livelihoods. https://en.wikipedia.org/wiki/Mexican_Repatriation
This was an unconstitutional action on par with the Japanese internment, but few people even know it happened. Maybe someone needs to write a popular novel so they can make a movie about it.