 In 2012, Supreme Court Justice Anthony Kennedy wrote this claim, and the majority opinion in the case, Arizona vs. United States. In the state's most populous county, these aliens are reported to be responsible for a disproportionate share of serious crime. The bill I'm about to sign into law, Senate Bill 1070, represents another tool for our state to use as we work to solve a crisis. The Supreme Court was ruling on the constitutionality of Arizona's Senate Bill 1070, a strict immigration law that requires police officers to verify citizenship status of all people they detain or arrest. ProPublica traced Kennedy's claims back to its source, and we found that Kennedy's numbers didn't add up. To back up his claim, Kennedy cited a report from the Center for Immigration Studies, a non-profit that advocates for reducing immigration. Kennedy described the report as, quote, estimating that unauthorized aliens comprise 8.9% of the population and are responsible for 21.8% of the felonies in Maricopa County. The figure about felonies came from a study published by Maricopa County Attorney Andrew Thomas using data from 2007. He was elected on a broad anti-illegal immigration agenda. Illegal immigration is a brutal battle that Andrew Thomas understands. He has led the charge against human smugglers. But the Center for Immigration Studies got the number wrong. The study claims 21.8% is an estimate, but the actual analysis of the data shows undocumented immigrants were responsible for 18.7% of felony convictions in the county, not 21.8%. To be clear, the 18.7% figure is still disproportionately high compared to undocumented immigrants' share of the population. But there are even more problems with this data. Thomas, the county's attorney, pursued felony convictions against undocumented immigrants for three specific crimes that are tied to being in the U.S. illegally. I had an informal policy. I called it half-jokingly the Thomas No Amnesty Policy, which was I required that they get a felony conviction. First, Thomas prosecuted undocumented immigrants being smuggled into the U.S. as co-conspirators, so people that were previously treated as crime victims were now charged with a felony. Almost all smuggling cases Thomas prosecuted were against undocumented immigrants, and no other county attorney in Arizona prosecuted smuggled immigrants this way. Second, Thomas aggressively prosecuted immigrants who committed criminal impersonation, for example putting a fake social security number on a job application. Third, Thomas also aggressively prosecuted forgery, like fake identification cards. And again, Thomas ran for office on an anti-immigrant platform, so it's no surprise he aggressively prosecuted three nonviolent crimes that are most often committed by undocumented immigrants as they attempt to enter or work in the U.S. If we remove these three crimes from the analysis, we find undocumented immigrants made up 13.8% of all felony convictions in Maricopa County in 2007. It's still more than their share of the population, but significantly less than the 21.8 number Kennedy cited in the Supreme Court's ruling. Oh, also we should note that Thomas was disbarred by the state of Arizona five weeks before the release of the court's ruling. In its documentation, the Arizona State Bar alleged Thomas committed 32 ethical violations as the attorney for Maricopa County. The Supreme Court's ruling in Arizona vs. the United States said a broad precedent for future cases about immigration enforcement by local police. Yet, the math did not up, and nobody bothered to check.