Reihan fears that they are damaging the Republican party:
My sense is that the disarray and dysfunction currently on display in Congress flows from campaign finance regulations that have weakened broad-based, national political parties while strengthening solo political entrepreneurs. Many of us hope that some future Republican presidential nominee will be able to impose order on the GOP’s congressional wing. But it is just as easy for me to imagine a popular Republican president facing ferocious attacks from a minority of opportunistic legislators aided by allied independent expenditure groups.
Carney explains how outside groups apply pressure:
In Washington, it’s called the “inside-outside game”: Beltway players reach out to the grassroots to apply pressure to elected officials. When Cruz and friends do it, I call it the Tea Party Whip Operation. … Often the Tea Party Whip Operation involves outside groups such as the Senate Conservatives Fund, Heritage Action, the Club for Growth, and FreedomWorks. And these groups’ involvement is what really upsets other Republicans.
Dickerson thinks the actions of these groups helps explain why Cruz is loathed by so many of his collegues:
Cruz says he has not attacked Republicans specifically, but in his alliance with Jim DeMint, the former South Carolina senator and now president of the Heritage Foundation, he has done something more powerful. He has helped raise money to run advertisements against incumbent Republican senators.
Zeke Miller profiles Heritage Action:
Republican leadership fears it will bear the blame for government shutdown, endangering vulnerable Republicans in 2014. But for Heritage and its allies, the resonance of their message is more than a moral victory. “I think that this campaign has already been very successful in the sense that we’ve driven the narrative in the last two months about how Obamacare is literally falling apart,” Needham says. “There’s been huge national attention in the media and the grassroots. That’s a great thing for the country and a great thing for us.”
The Dish 