safety officer, or labor organization to agree to the terms of a proposed contract. (b) No preemption Nothing in this section shall be construed to preempt any law of any State or political subdivision of any State with respect to strikes by public safety officers. 7. Existing collective bargaining units and agreements A certification, recognition, election-held, collective bargaining agreement, or memorandum of understanding that has been issued, approved, or ratified by any public employee relations board or commission or by any State or political subdivision or its agents and is in effect on the day before the date of enactment of this Act shall not be invalidated by the enactment of this Act. 8. Construction and compliance (a) Construction Nothing in this Act shall be construed— (1) to preempt or limit the remedies, rights, and procedures of any law of any State or political subdivision of any State that provides comparable or greater rights and responsibilities than the rights and responsibilities described in section 4(b)