President Donald Trump's longtime political ally Roger Stone invoked his Fifth Amendment protection as he declined to share documents and testimony with members of the Senate Judiciary Committee, according to a letter posted Tuesday by the committee's top Democrat, Sen. Dianne Feinstein. "Mr. Stone's invocation of his Fifth Amendment privilege must be understood by all to be the assertion of a Constitutional right by an innocent citizen who denounces secrecy," Stone's attorney, Grant Smith, said in the letter, dated Dec. 3.