by anyone, including potential terrorists. During the Cold War, he supported Reagan's Strategic Defense Initiative, intended to replace the "strategic offense" doctrine of mutual assured destruction with strategic defense. Paul favors legal immigration to the United States—today, approximately 1 million people per year— and opposes illegal immigration. Paul believes illegal aliens take a toll on welfare and Social Security and would end such benefits, concerned that uncontrolled immigration makes the U.S. a magnet for illegal aliens, increases welfare payments, and exacerbates the strain on an already highly unbalanced federal budget. Paul believes that illegal immigrants should not be given an "unfair advantage" under law. He has advocated for a "coherent immigration policy", and has spoken strongly against amnesty for illegal aliens because he believes it undermines the rule of law, grants pardons to lawbreakers, and subsidizes more illegal immigration. Paul voted for the Secure Fence Act of 2006, authorizing an additional 700 miles (1100 kilometers) of double-layered fencing between the U.S. and Mexico mainly because he wanted enforcement of the law and opposed amnesty, not because he supported the construction of a border fence. Paul believes that mandated hospital emergency treatment for illegal aliens should be ceased and that assistance from charities should instead be sought because there should be no federal mandates on providing health care for illegal aliens. Paul also believes children born in the U.S. to illegal aliens should not be granted automatic birthright citizenship. He has called for a new Constitutional amendment to revise Fourteenth Amendment principles and "end automatic birthright citizenship", and believes that welfare issues are directly tied to the illegal immigration problem. Terrorism Letters of marque and reprisal Calling the September 11, 2001, attacks an act of "air piracy", Paul introduced the Marque and Reprisal Act of 2001. Letters of marque and reprisal, authorized by article I, section 8 of the Constitution, would have targeted specific terrorist suspects instead of invoking war against a foreign state. Paul reintroduced this legislation as the Marque and Reprisal Act of 2007. He voted with the majority for the original Authorization for Use of Military Force Against Terrorists in Afghanistan. In April 2009, following the Maersk Alabama hijacking, he proposed issuing letters of marque to combat the problem of piracy in Somalia. Airport security Following the 9/11 attacks, Paul "opposed the federalization of airport security, the creation of the DHS and increased police state measures, but did