HA! they're gonna do it whether we 'allow' them access or not... As if 'We' had any say in it...
Right now, they have the best of both worlds: all access and no responsibilities.
Part of that is that 'domestic terrorist' has not been defined. As we can see with the IRS, whether you agree or disagree, the fact is that they specifically targeted companies with names thought to be associated with a specific political bent. They had 'responsibilities' and 'oversight', but the people in charge of that either didn't care or purposefully broke the 'rules'. Does 'the State' then designate those 503c orgs as 'terrorists'?
If you start defining terrorism the same way the State department does: "the use of violence and intimidation in the pursuit of political aims."
then that opens the flood gates of every agency who has armed agents to be defined as a 'terrorist' organization. Why does the EPA/IRS/Dept. of Ed have armed agents? Hell, try not paying your property tax and see what the local Sheriff's dept. does... This country is based on taxation by threat of violence...
When (s)he uses it in an ill-conceived manner.
While that may sound glib, it's an unfortunate truth: you cannot anticipate all the ways in which an individual can fly off the handle. The best you can do is to provide for earlier, softer escape routes (e.g. counseling, family cohesion, social security).
Since gun control seems to go nowhere, maybe it is time to reconsider allowing the NSA domestic access?