“The power to tax involves the power to destroy...”
What, then? Let's start by remembering that despite all the buck-passing and obfuscation, oppression is carried out by people. Sure, they work for giant bureaucracies, but they're individually responsible for their actions. They can claim to have been "following orders" (or policies, which are just vague orders), but that excuse didn't fly in 1945 and won't now.
Who are these people? At the IRS there's Lois Lerner, who refused to testify before Congress, claiming her 5th Amendment right. There are Daniel Werfel and Douglas Shulman, masters of the Sergeant Schultz defense--- "I see nothing–NOTHING!" Then there are the unnamed IRS agents who actually carried out the harassment. There is no reason why the home addresses, telephone numbers and photographs of these people shouldn't be made public, just as the personal information of concealed-weapons permit holders has been. Google Earth photos of their homes would be nice, too.
I would never suggest that these people be threatened or harmed in any way. SEIU thugs, Muslim terrorists, neo-Nazis and other scum do that. But several people picketing their homes to identify them and their crimes against the Constitution might have a salutary effect.
Letters (remember them?) and emails politely but firmly condemning their actions and expressing disappointment in their characters could also be effective. Remember, no insults, no invective, no vandalism, certainly no interference with their families in any way. We're not Occupiers and should demonstrate what we preach, respect for individual rights.
What's the goal? One, keeping Constitutional issues in the public consciousness. Two, reminding bureaucrats that they can and will be held individually responsible for their actions. Three, motivating others to refuse illegal orders and resist oppressive policies. You never know---it might catch on.