In "Effectively Curbing the GST Exemption for Perpetual Trusts," I criticized the Treasury Department’s proposal for dealing with perpetual trusts. My objection is that Treasury’s approach would leave many trusts and much wealth GST-exempt for much longer than Congress originally intended. For perpetual trusts created before enactment, Treasury’s approach would allow them to continue to be unburdened by a durational limit. For perpetual trusts created after the effective date of enactment, Treasury’s approach would still allow them to qualify for the GST exemption, but would have the exemption expire 90 years after the trust was created.
Waggoner, Lawrence W. "Effectively Curbing the GST Exemption for Perpetual Trusts." Tax Notes 135 (2012): 1267-72.