Ian,
I think this quote acts as if there is not a simple baseline being promoted by conservatives, ie. the status quo when a corporation makes a particular investment. Regulations that are put in place before such an investment do not require compensation, but any regulation must compensate those who invested with expectations of profit based on lack of such regulations.
In fact, this is the standard promoted in Eastern Associated Enterprises [June 25, 1998]
O'Connor for the Court argued that imposing liability for paying the health care benefits of former mining employees on mine companies "interferes with the claimant's reasonable investment-backed expectations" and "attaches new legal consequences to [an employment relationship] completed before its enactment." Like the Ex Post Facto Clause in penal legislation, O'Connor argued that "the Takings Clause provides a similar safeguard against retrospective legislation concerning property rights."
This is an intellectually cogent if politically deadly position for conservatives to defend. And they are increasingly doing so through their control of the Supreme Court.
-- Nathan Newman