Sanford rejects call for resignation from lieutenant governor *NEW: "I am not going to be railroaded out of this office," governor says *NEW: He defends record, says critics are trying to exploit weakened political position *Lieutenant governor calls investigation too much of a distraction for South Carolina *Possible impeachment is expected to dominate state House GOP retreat's agenda updated 6:01 p.m. EDT, Wed August 26, 2009 http://www.cnn.com/2009/POLITICS/08/26/mark.sanford/