In an interview with ABC News, Trump, who, like Cruz, is running for the GOP nomination for president, said: "Cruz fought like hell to get Justice Roberts in there. Justice Roberts turned out to be an absolute disaster. He turned out to be an absolute disaster because he gave us Obamacare."
But some of these critics may be making the same mistake that Trump made: thinking that Supreme Court justices are supposed to be robots or partisan hacks.
Obviously, Roberts is a career-long legal and political conservative, just as his Democratic-appointed colleagues are political liberals. But members of both "blocs" call cases the way they see them -- and sometimes the call is one the justice's "home team" objects to. As I wrote earlier, Obama appointees Justices Sonia Sotomayor and Elena Kagan have voted against the legal position proposed by the administration.
Mark Tushnet, a professor at Harvard Law School, explains the situation well in his book "In the Balance: Law and Politics on the Roberts Court":
"Judging from the personnel alone, you'd expect that the Roberts Court would be a reliably conservative court. But, as conservative outrage at the Affordable Care Act decision indicates, it isn't. Not completely reliable, that is — not a ventriloquist's puppet for the Republican Party. Yet, though the picture is mixed, the Roberts Court's decisions correspond to the main constitutional positions associated with the Republican Party of the early 21st century."
Trump seems to think Roberts should be a ventriloquist's dummy for the Republican Party. Some of the chief justice's liberal detractors seem to think he really is one.
In an article in the Nation in 2014 (published before the second ruling in which Roberts voted to uphold a challenged provision of the Affordable Care Act) William Greider wrote:
"Republicans like to talk about impeaching President Obama, but there is a far more deserving candidate for impeachment -- Chief Justice John Roberts of the Supreme Court. While the Republicans in Congress have blocked Democrats from enacting much of substance, the GOP majority in control of the court has been effectively legislating on its own, following an agenda neatly aligned with their conservative party."
Trump hasn't come out (yet) for impeaching Roberts. But keep an eye on his Twitter feed.