"The president said at a news conference that the new program is 'the right thing to do' in light of Congress's failure to pass the administra*tion's proposed revision of the Immigration Act," Scalia, a Reagan appointee, wrote in his dissent. "Perhaps it is, though Arizona may not think so. But to say, as the Court does, that Arizona contradicts federal law by enforc*ing applications of the Immigration Act that the President declines to enforce boggles the mind."
Scalia went on to write:
Arizona bears the brunt of the country's illegal immigration problem. Its citizens feel themselves under siege by large numbers of illegal immigrants who invade their property, strain their social services, and even place their lives in jeopardy. Federal officials have been unable to remedy the problem,and indeed have recently shown that they are unwilling to do so. Thousands of Arizona's estimated 400,000 illegal immigrants—including not just children but men and women under 30—are now assured immunity from en*forcement, and will be able to compete openly with Ari*zona citizens for employment.
Scalia also repeatedly referenced Obama's policy of prosecutorial discretion, which directs Immigration and Customs Enforcement agents to prioritize deporting the illegal immigrants who are frequent border crossers, have committed crimes, or recently entered the country illegally. The Obama administration has deported a record number of illegal immigrants, but its prosecutorial discretion policy still draws the ire of illegal immigration hawks.