No mention here of Roberts even partially dissenting;
Justice Scalia dissented and said that he would have upheld the entire law. Justice Thomas likewise would uphold the entire law as not preempted by federal law. Justice Alito agreed with Justices Scalia and Thomas regarding Sections 5(C) and 6, but joined with the majority in finding Section 3 preempted.
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In his dissenting opinion, Justice Scalia commented on President Obama’s recent announcement suspending deportation of illegal immigrants who came to the U.S. as children — an issue not actually part of the Arizona case:
It has become clear that federal enforcement priorities—in the sense of priorities based on the need to allocate “scarce enforcement resources”—is not the problem here. After this case was argued and while it was under consideration, the Secretary of Homeland Security announced a program exempting from immigration enforcement some 1.4 million illegal immigrants under the age of 30…
The husbanding of scarce enforcement resources can hardly be the justification for this, since the considerable administrative cost of conducting as many as 1.4 million background checks, and ruling on the biennial requests for dispensation that the non-enforcement program envisions, will necessarily be deducted from immigration enforcement. 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 Administration’s proposed revision of the Immigration Act. Perhaps it is, though Arizona may not think so. But to say, as the Court does, that Arizona contradicts federal law by enforcing applications of the Immigration Act that the President declines to enforce boggles the mind.
Which means the president is supposed to be enforcing the current law as written and not the imagined revisions he'd like to enforce.