Answer:
Senator Simpson.
Step-by-step explanation:
Senator Simpson was the prominent person who gave public support about Stevenson's case. His support was significant because of his position as the Republican party's whip.
As the whip of the Republican party, Senator Simpson was the person who ensured that every decision and action among the Republican senators took place accordingly and efficiently. His support to Joe and Stevenson's case also garnered a lot of media attention and public support.