“All modern presidents have done this,” said Kenneth Mayer, a University of Wisconsin political science professor who has studied the presidency extensively. “All presidents utilize the tools of executive power to implement policies.”

To be sure, Obama is not the first president to be accused of overstepping the bounds of his authority – a point emphasized Friday by White House press secretary Jay Carney, who said, “it is funny to hear Republicans get upset about the suggestion the president might use legally available authorities … when, obviously, they supported a president who used executive authorities quite widely.”…

Timothy Jost, a law professor at Washington and Lee University and a strong supporter of the healthcare law, argued that presidential administrations commonly extend compliance deadlines, particularly for sweeping and complex laws such as the Affordable Care Act.

Republican administrations, he said, presided over similar delays in the execution of laws approved by Congress.

“This is not anything new – it’s just now the shoe’s on the other foot,” Jost said. “I think they’re taking a reasonable approach and I think there’s a legal basis for what they’re doing.”