Ilya Shapiro, a lawyer for the libertarian Cato Institute, said the immigration order is the "starkest example" of what he called the president's "pattern of lawlessness."
The question now is whether the president's immigration action will influence the thinking of the justices, and particularly of Roberts, as they consider in the upcoming healthcare case whether the president exceeded his authority.
At issue is whether the administration must abide by one provision in the healthcare law, which says subsidies may be paid to those who enrolled in state health exchanges, or whether the president can extend those benefits to include people who signed up on the federally run exchange.
The administration argues the healthcare law, read as whole, shows Congress intended to make the subsidies available nationwide. But critics are appealing to Roberts and the court's conservatives, arguing the president and his advisors have no power to unilaterally change a law passed by Congress.
Their argument echoes the criticism voiced over Obama's immigration directive, accusing the president of trying to fix a broken system by acting on his own rather than waiting for Congress.
Experts say that legally the healthcare case is a close call. If so, the outcome may turn on whether the justices are inclined to give the president the benefit of the doubt, or whether they believe it's time to rein him in.
Obama's bold decision to press ahead with his immigration order in the wake of the GOP victories in the midterm election will not escape the attention of the court's conservatives.
Shapiro said the new immigration plan will "confirm the chief justice's view" that the court should not allow the administration to revise laws passed by Congress.