Former Labor Secretary Tom Perez was chosen to be the new chairman of the Democratic National Committee on Saturday, defeating Minnesota Congressman Keith Ellison.
Soon after, President Trump tweeted, "Congratulations to Thomas Perez, who has just been named Chairman of the DNC. I could not be happier for him, or for the Republican Party!"
Perez responded by writing, "Call me Tom. And don't get too happy. @keithellison and I, and Democrats united across the country, will be your worst nightmare."
Trump wasn't done slamming the DNC chair selection. He then tweeted on Sunday, "The race for DNC Chairman was, of course, totally 'rigged.' Bernie's guy, like Bernie himself, never had a chance. Clinton demanded Perez!"
Perez commented to that tweet on CNN, "Congressman Ellison and I got a good kick out of that. Donald Trump, up in the morning tweeting about us. You know, our unity as a party is our greatest strength and it's his worst nightmare."