Major provisions of Arizona’s S.B. 1070 were held unenforceable by the Supreme Court because they conflict with federal law, though the Court unanimously upheld its most controversial provision. So the biggest immigration case in U.S. history was a mixed result, one in which President Barack Obama won more than Governor Jan Brewer, in a case reminding us that America’s Supreme Court is anything but conservative.

Two important points at the outset about Arizona v. United States that the media isn’t discussing.

First, this case had nothing to do with whether Arizona’s law is constitutional. Despite the rhetoric from the White House and Eric Holder, the administration did not raise any constitutional challenges in court.

Second, Justice Anthony Kennedy was not the swing vote in this case. Since liberal Justice Elena Kagan was recused from this case, you couldn’t get to five votes without Chief Justice John Roberts. And this case was the latest–and one of the biggest–reminders that Roberts is a moderate conservative, not a conservative, as Roberts sided with the left.

The Supreme Court examined just four provisions of S.B. 1070. The Court was determining for each of those four whether federal statutes preempted Arizona’s law, since the Constitution specifies that when the two are in conflict, federal law wins.

Kennedy wrote the majority opinion, beginning, “The federal power to determine immigration policy is well settled. Immigration policy can affect trade, investment, tourism, and diplomatic relations for the entire Nation, as well as the perceptions and expectations of aliens in this country who seek the full protection of its laws.”

He acknowledged that states bear a significant burden on this issue. “The pervasiveness of federal regulation does not diminish the importance of immigration policy to the states. Arizona bears many of the consequences of unlawful immigration.”

Kennedy added, “Federalism, central to the constitutional design, adopts the principle that both the national and state governments have elements of sovereignty the other is bound to respect.” The Constitution creates a system of dual sovereigns.

He then discussed the different forms of preemption. “There is no doubt that Congress may withdraw specified powers from the states by enacting a statute containing an express preemption provision.” That’s the easy way (and it should be the only way). But Kennedy also described the much broader concept of field preemption, under which “states are precluded from regulating conduct in a field that Congress, acting within its proper authority, has determined must be regulated by its exclusive governance… so pervasive … that Congress left no room for the states to supplement it.” The majority held field preemption invalidates the provision making it a state crime for noncitizens not to carry federally-required documents showing they’re allowed in the country.

Turning to other sections of S.B. 1070, the Court held some others trumped by conflict preemption, where state laws conflict with Congress’ purposes and goals. For example, striking the section making it a state crime in Arizona for an illegal alien to seek work, Kennedy said, “Congress made a deliberate choice not to impose criminal penalties on aliens who seek, or engage in, unauthorized employment.” The Court likewise held preempted the new authority to arrest without a warrant those suspected of being deportable from the United States.

The only challenged provision to survive was the one empowering Arizona police to ask you for your immigration papers, and to check with federal authorities (who by law must answer) regarding the immigration status of anyone lawfully detained for other reasons. This was a significant victory for conservatives, since it was the most controversial and publicized aspect of the law.

Justice Antonin Scalia took the unusual step of reading part of his dissent from the bench. “The United States is an indivisible Union of sovereign states. Today’s opinion … deprives states of what most would consider the defining characteristic of sovereignty: the power to exclude from the sovereign’s territory people who have no right to be there. Neither the Constitution itself nor even any law passed by Congress supports this result.”

Scalia went on in what would have been an excellent majority opinion, adding, “As a sovereign, Arizona has the inherent power to exclude persons from its territory, subject only to those limitations expressed in the Constitution or constitutionally imposed by Congress. That power to exclude has long been recognized as inherent in sovereignty.”

He reached the core of why S.B. 1070 is okay by saying, “What this case comes down to, then, is whether the Arizona law conflicts with federal immigration law–whether it excludes those whom federal law would admit or admits those whom federal law would exclude. It does not purport to do so.”

Showing that historically the states were primarily responsible for immigration, and the Framers of the Constitution left it that way, Scalia surmised, “Arizona is entitled to have its own immigration policy–including a more rigorous enforcement policy–so long as that does not conflict with federal law. The Court says, as though the point is utterly dispositive, that it is not a crime for a removable alien to remain present in the United States. It is not a federal crime, to be sure. But there is no reason Arizona cannot make it a state crime for … any illegal alien … to remain present in Arizona.”

Responding to the Obama administration’s major arguments, Scalia added, “Of course there is no reason why the federal executive’s need to allocate its scarce resources to illegal immigration should disable Arizona from devoting its resources to illegal immigration in Arizona that in its view the federal executive has given short shrift.”

Justice Clarence Thomas set forth the most clearly principled dissent in the case. “Nothing in the text of the relevant federal statutes indicates that Congress intended enforcement of its registration requirements to be exclusively the province of the federal government.”

Thomas rejects the idea of implied preemption, where a court can say federal law preempts state law without declaring it means to do so. “I have explained that the ‘purposes and objectives’ theory of implied preemption is inconsistent with the Constitution because it invites courts to engage in freewheeling speculation about congressional purpose that roams well beyond statutory text… Under the Supremacy Clause, pre-emptive effect is to be given to congressionally enacted laws, not to judicially divined legislative purposes.”

Justice Samuel Alito took a middle course. While Scalia and Thomas would uphold all four provisions, and the majority upheld one but took down three, Alito would have gone two and two.

The best line went to Scalia, who made the very rare move of showing the connection to current politics. He summed up well the one question presented by this case: “Are the sovereign states at the mercy of the federal executive’s refusal to enforce the nation’s immigration laws?” Today the Supreme Court answered yes, unfortunately.

Breitbart News legal contributor Ken Klukowski is a fellow with the American Civil Rights Union.