The RNC chose Fox for first debate but rankled conservatives by entertaining CNN

Many top Republicans are convinced that the debates — what format they take, who is allowed to participate and how they are designed — will play an outsize role in determining who wins the primary. They may also winnow down the field: Party officials say they are likely to implement thresholds in order for candidates to qualify for the debates; participation in the first debate could include standards like somewhere between 40,000 and…