Thirty Republican former members of Congress released an open letter Thursday declaring that they cannot support Donald Trump for president. They claim the GOP nominee does not possess the temperament required to be president and does not reflect their principles. “Given the enormous power of the office, every candidate for president must be judged rigorously in assessing whether he or she has the competence, intelligence, knowledge, understanding, empathy, judgment, and temperament necessary to keep America on a safe and steady course,” they wrote. “Donald Trump fails on each of those measures, and he has proven himself mainfestly unqualified to be president.” The signatories include former New Hampshire Sen. Gordon Humphry and former Minnesota Rep. Vin Weber. The letter’s organizer said some of them plan on voting for Democratic nominee Hillary Clinton, while others will cast their ballot for Libertarian nominee Gary Johnson or a write-in candidate.