Trump endorses primary challenger for 'WEAK' and 'toxic' GOP Senator Jeff Flake
Donald Trump during CNN debate (Photo: Screen capture via video)

President Donald Trump on Thursday endorsed Kelli Ward, the woman who is running a primary challenge against Sen. Jeff Flake (R-AZ).

"Great to see that Dr. Kelli Ward is running against Flake Jeff Flake, who is WEAK on borders, crime and a non-factor in Senate," Trump wrote on Twitter. "He's toxic!"

Flake earlier this month said that he wished that the Republican Party had stood up to Trump and his embrace of the "birther" conspiracy theory about former President Barack Obama's birth certificate.

"During [Trump] rallies, when chants 'lock her up,' we shouldn’t be the party for jailing your political opponents," Flake said in early August during an interview with NBC's Chuck Todd. "And anybody at that rally — at those rallies ought to stand up and say, 'That’s inappropriate, we shouldn’t be doing that.'"