Sen. Mark Udall apologized Monday for invoking ISIS-beheaded journalists James Foley and Steven Sotloff in a debate Saturday with Republican challenger Cory Gardner.

Talking Points Memo received a statement from Udall beginning, “When addressing ISIL during this weekend’s debate, I should not have invoked the names of James Foley and Steven Sotloff. It was inappropriate and I sincerely apologize.”

Many, like National Review’s Jim Geraghty, harshly criticized Udall for putting words in the mouths of the murdered journalists. As he asked, “How do the Sotloff and Foley families feel about Senator Udall invoking their sons as his supporting allies in this debate?”