Ramesh Ponnuru of National Review Online ponders the president’s proper role in defending legislation of questionable constitutionality.
Perhaps a constitutionally conscientious president should … direct his aides to defend the challenged statutes unless the constitutional case against them is overwhelmingly strong. Or perhaps the executive branch should reach its own best judgment about the constitutional merits of a lawsuit and share that judgment with the courts. The text of the Constitution does not tell a president what to do in such matters, and nor, it seems to me, do the logic and structure of the Constitution. If a president has doubts about the constitutionality of a statute—even doubts that fall short of a firm conviction—he can refrain from defending it in court without embracing “lawlessness.” …
Anyway, different administrations will naturally reach different conclusions about when a statute’s constitutional “repugnance” is “obvious.” I am not sure what is gained by moving from the claim “this administration’s view that this statute is unconstitutional is obviously absurd” to “this administration’s view that this statute is unconstitutional is obviously absurd, and it is therefore shirking its duty to defend the statute in court.” The first claim is damning enough if true, and the second depends on its truth for all its force.
Now to the second question, regarding the Obama administration’s 2011 decision to stop defending the Defense of Marriage Act. Was that act so obviously unconstitutional as to merit no defense? Apparently no justice of the Supreme Court thought so: When the Court ruled on the law in 2013, four of the justices voted to uphold its constitutionality and the other five joined an opinion that gently criticized the administration for abandoning the defense.