The National Republican Senatorial Committee is taking an unusually aggressive posture toward one of its conservative antagonists, putting out word that GOP groups shouldn't hire a consulting firm that works with the Senate Conservatives Fund. The New York Times's Jonathan Martin reports: 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 is trying to...