Paul Manafort committed bold crimes that go “to the heart of the criminal justice system,” special counsel Robert Mueller’s prosecutors wrote in a memo unsealed Saturday in which they endorsed a stiff punishment for the former Trump campaign chairman.

“His deceit...extended to tax preparers, bookkeepers, banks, the Treasury Department, the Department of Justice National Security Division, the FBI, the Special Counsel’s Office, the grand jury, his own legal counsel, Members of Congress, and members of the executive branch of...