John D. Feeley, the former U.S. Ambassador to Panama who announced his resignation in January, penned a scathing op-ed in The Washington Post on Friday, revealing he stepped down because of President Donald Trump's policies and his rhetoric toward immigrants. "I resigned because the traditional core values of the United States, as manifested in the president’s National Security Strategy and his foreign policies, have been warped and betrayed," he wrote. "I could no longer represent him personally and remain faithful to my beliefs about what makes America truly great." Feeley’s resignation letter was leaked to the press in January. “Leaking a sitting ambassador’s personal resignation letter to the president, as mine was, is something else," he said. "This was a painful indication that the current administration has little respect for those who have served the nation apolitically for decades.” Feeley, whose resignation took effect Friday, added that Trump’s plans to build a wall along the border and his “jingoistic chest-beating” in front of the international community make the U.S. “undoubtedly less welcome in the world today.” Career diplomats have been leaving the State Department in droves, and many of the positions are still empty, depriving the department of expertise.