Not sure, I find it impossible to believe that the establishment will give anti-establishment political organizations a fair shake, which is exactly what happened in this scandal. These orgs are not partisan per se, for all I know there's some anti-establishment Democrats out there that they've supported (e.g. many of my home state's Missouri Democratic "liberals" are to the right of the national Republican party/establishment), and they've collected many Republican establishment scalps.
But one of the problems is that before the fact investigation just doesn't work, for how can you tell if an org is going to do impermissible actions? The only one that counts is coordination with a campaign, which is by definition secret, because the other impermissible actions (at least that I know of) are by definition public.
Although, now that I think about it, I'm not sure where the lines are drawn. The NRA-ILA explicitly "endorses" some politicians in addition to grading all they can afford to do, and boy do anti-gun Republicans squeal like stuck pigs when the NRA tells the truth, or, worse, goes after them with a rusty knife like they did with F rated Lugar. So explicit endorsement per se does not cross the line....
Look at the examples of the suppressed orgs that said their purpose was teaching people about the Constitution. That's obviously subversive nowadays (heck, look at the IRS ex-Commissioner I think who said he didn't know the contents of the 1st Amendment), and yet they somehow deserve extra scrutiny?
Look up the concept of prior restraint, which the government is seldom allowed to do when it comes to enumerated Constitutional rights. I.e. they can't order the press to not do something, only prosecute them afterwords.