Last week, we wrote about how hard-right groups like the Club for Growth dominated outside spending in the last Republican primaries. We noted that outside money was far more successful in these contests than it was in the general elections, and urged reporters and political observers to keep a close eye on whether the GOP establishment would fight back with super PACs and dark money of its own.

The answer came sooner than we thought. On Sunday, The New York Times broke the news that Karl Rove’s Crossroads groups, a mainstream Republican outfit that is the biggest outside spender in the nation, will create a new super PAC called the Conservative Victory Project to “recruit seasoned candidates and protect Senate incumbents from challenges by far-right conservatives and Tea Party enthusiasts who Republican leaders worry could complicate the party’s efforts to win control of the Senate.”

The outside money battle for control of the Republican Party is underway—and reporters should cover it closely, at both the local and national levels.

A first step is to report on spending by super PACs and political nonprofits in local Congressional races, and in issue ads targeted at particular districts or officials. An issue ad on a pressing vote before Congress may signal that the targeted official is on the radar of national spending groups, and threaten a primary challenge to come. The support or opposition of certain outside groups can also speak volumes about a politician’s beliefs and approach to governing. The support of the Club for Growth or Americans for Tax Reform, for example, may be a better indication that a Republican candidate will be willing to defy party leadership to stick to a hard line on tax and spending issues than any speech or declaration.

It will be particularly interesting to note where mainstream groups such as the Conservative Victory Project jump in. American Crossroads’s president, Stephen Law, described the group’s goal as supporting “the most conservative candidate who can win”—so its opposition essentially represents a decision by establishment leaders that a candidate is too extreme to be electable.

A second area that reporters should examine is where mega-donors line up. The New York Times story on the Conservative Victory Project states that “the biggest donors in the Republican Party” are backing the group, but then doesn’t provide any names. In the context of the growing split within the party, this raises major questions. For example, mega-donor Bob Perry is one of the top five donors to both American Crossroads and the Club for Growth Action PAC. Sheldon Adelson and his wife Miriam were jointly the largest donor to American Crossroads, but they also supported Newt Gingrich’s insurgent presidential campaign attacking Mitt Romney from the right. Will these mega-donors and others like them—who play such a crucial role in setting super PACs’ directions and making them viable—choose sides now that there is open confrontation between mainstream and far right groups?

Finally, the accuracy and the credibility of the messages in outside groups’ ads
will merit close scrutiny. John Feehery, a Republican strategist who managed communications for former House speaker Dennis Hastert and then-Minority Whip Tom DeLay, reminded us that Republican primary voting tends to be dominated by staunch conservatives who are more likely to support hard line policies. “So what ends up happening,” Feehery said, “is that the more moderate groups get forced to out-conservative the conservatives and then it gets real ugly.”

Some groups on the establishment side of Republican primary battles—such as the Conservative Victory Project or the Texas Conservatives Fund, a group that unsuccessfully opposed Tea Party Senate candidate Ted Cruz in the primary—wrap themselves in conservative names, and their messages may follow suit. Reporters should be prepared to sniff out groups that attack conservatives from the right even as they are underwritten by the GOP establishment and favor more moderate candidates.

Sasha Chavkin covers political money and influence for CJR's United States Project, our politics and policy desk. He has written for ProPublica, the Center for Public Integrity, and The New York World. Follow him on Twitter @sashachavkin.