Since the REAL ID Act passed in May 2005, five states have passed anti-REAL ID legislation that rejects implementation of the Act. Most recently, Washington passed legislation with strong support that dictates that the state not spend any money implementing the REAL ID Act unless privacy and security concerns are addressed. Initially drafted after the Sept. 11 attacks and designed to discourage illegal immigration, the law attempts to make it more difficult for terrorists to fraudulently obtain US driver's licenses and other government IDs by mandating that states require birth certificates or similar documentation and also consult national immigration databases before issuing IDs. The law is also meant to make it more difficult for potential terrorists to board aircraft or enter federal government buildings. After controversy and strenuous opposition from civil libertarians, it finally passed in 2005 as part of an emergency supplemental appropriations defense spending bill. Other state lawmakers have previously expressed concern about possible problems expected to accompany the implementation of the REAL ID Act, fearing that they will not be able to comply with the law's requirements before a May 2008 deadline. In March, Homeland Security responded to these concerns by extending the deadline for compliance by 18 months.