Rep. Devin Nunes , California Republican and chairman of the House Permanent Select Committee on Intelligence, said Monday that he has not seen a scrap of evidence that Trump campaign officials had any contact with Russian officials, but his assurances failed to silence the growing drumbeat of calls for a special prosecutor. Rep. Darrell E. Issa of California, a former chairman of the House Oversight and Government Reform Committee, became the most prominent Republican to join Democrats in demanding the appointment of a special prosecutor to investigate the former Cold War foe’s meddling in the presidential election and an alleged Trump campaign connection to Russian intelligence agents.