(Excerpt) In a warning shot to outside conservative groups, the National Republican Senatorial Committee this week informed a prominent Republican advertising firm that it would not receive any contracts with the campaign committee because of its work with a group that targets incumbent Senate Republicans. Even more striking, a senior official at the committee called individual Republican Senate campaigns and other party organizations this week and urged them not to hire the firm, Jamestown Associates, in an effort to punish them for working for the Senate Conservatives Fund, a group founded by Jim DeMint, then a South Carolina senator, that...
