Fred Barnes, writing in the Wall Street Journal:
American Crossroads is an "independent expenditure" group or "super PAC" which operates as a tax-exempt organization under section 527 of the Internal Revenue Code. It is committed to boosting Republican candidates, mostly with TV ads, but it is legally barred from coordinating directly with their campaigns. It has an all-star team of unpaid advisers including former George W. Bush aides Karl Rove and Ed Gillespie, and Mississippi Gov. Haley Barbour.
Its goal in 2012—and the goal of Republicans in general—is parity with Democrats in campaign spending. That would be no small feat, as Democrats have gained a significant edge in recent elections, and overall Democrats and pro-Democratic groups remain in the lead. Yet parity appears achievable....
Federal election law prohibits the Republican National Committee (or, for that matter, the GOP nominee's campaign) from having any involvement with independent expenditure groups such as American Crossroads or the American Action Network. The RNC, rather, has the traditional role of providing the indispensable "ground game." It funds state Republican parties, conducts voter-registration drives, works closely with the presidential nominee's campaign, and organizes the 72-hour plan to get voters to polls on Election Day.
American Crossroads and its allies are the critical new players in the Republican campaign. Their coalition didn't exist during the 2008 presidential race. In 2012, they'll have a huge impact and not only on individual races. Labor unions, by bonding with liberal groups, have moved the country to the left. Pro-Republican groups like AC hope to move America to the right.