(250923) -- WASHINGTON, Sept. 23, 2025 (Xinhua) -- U.S. President Donald Trump boards Marine One at the White House in Washington, D.C., the United States, Sept. 22, 2025. U.S. President Donald Trump on Monday signed an executive order designating Antifa as "a domestic terrorist organization," a move some experts believe lacks legal authority. (Xinhua/Hu Yousong)