It is clear that a U.S. passport will have increasing importance even for domestic travel. And the rise of the passport’s importance coincides uncannily with a new law giving the IRS power to revoke passports. Plainly, the easy answer to travel worries may be to dig out your passport, and they are already often in evidence in domestic air check in lines. But what if your passport is cancelled because you owe the IRS?
http://www.forbes.com/sites/robertwood/2016/03/14/as-u-s-passports-for-domestic-flights-loom-irs-can-now-revoke-passports/?ss=taxes#2097d9f534c3