Senate Republicans’ plan to include a debt backstop in their tax plan drew criticism from key outside conservative and business groups Tuesday and threatened to create a new division within the party as it moves to enact tax cuts.

The plan, advanced by Sens. Bob Corker of Tennessee and James Lankford of Oklahoma, would entail undoing some tax rate cuts or planned rate cuts if the debt rose faster than projected following the passage of the tax bill. That trigger would kick in if the tax cut did not boost economic growth as Republicans hope it will.