Even in its present form, this clause can do great damage.

FORBES: We Shouldn't 'Hire American'

In the UK, a form of protection and royalties are guaranteed in perpetuity by an exceptional clause in 1988 copyright legislation, but in much of the world copyright has now expired.

BBC: Design from Peter Pan stamp

Democrats did not include any provision or opt-out clause that would let states leave new Medicaid in the future or revert to Medicaid in its old form.

WSJ: Review & Outlook: New Medicaid's Roach Motel