It’s easy to make fun of the Supreme Court for relying on such ephemera as public opinion polls and “international opinion” in construing the Constitution – recall that when the Constitution was written, “international opinion” (which then, as now, meant “Europe”) was very, very much against democracy and the separation of powers, while barely a decade later the Continent was awash in the bloody tide of the guillotine – but what to do about it? Well, to stop this type of thing in its tracks, Congress could pass a statute simply stating that no court shall consider certain things in construing the meaning of the Constitution or federal statutes – such things to at least include public opinion polls or any “consensus” from outside our borders or that depends on, say, legislative enactments in a smaller number of the States than is required to amend the Constitution’s text in Article V. (You’d have to draw the thing more carefully than I’m doing now, but you get the idea).
Of course, the Atkins decision itself may likewise be easy to evade, since in at least some circumstances it appears to give state legislatures the wiggle room either to define who is “retarded” or easier yet to turn the question over to juries, who might yet be able to find that the nature of the crime (including what the Federal Sentencing Guidelines refer to as “more than minimal planning”) is evidence that the perp is not retarded. Since the Court has already held for some time that juries must consider retardation as a mitigating factor at sentencing, this is not a real sea change. In addition, because the sole focus is on the “mentally retarded criminal,” the decision does not appear to bar executing people like Rickey Ray Rector, the guy Clinton fried during the 1992 campaign, because Rector was not retarded at the time of the crime (he apparently lost a lot of brain when he shot himself in the head following the crime).