BUSINESS LAW-DQ

Article II, Section I of the United States Constitution provides that the President must “take care that the laws be faithfully executed.”  Presidents have used this authority to issue Executive Orders which are orders to federal agencies that are part of the Executive Branch and which contain detailed instructions on how laws enacted by Congress should be carried out. 

Does this provision of the Constitution allow a President to issue Executive Orders that directs federal agencies NOT to enforce specific laws that have been enacted by Congress?  Has any President ever issued an Executive Order that told a federal agency not to enforce a law?