Gov. Nikki Haley has rejected the Patient Protection and Affordable Care Act's offer of Medicaid expansion. The S.C. Senate is again considering legislation aimed at blocking other elements of that massive federal health care law.

But Obamacare's namesake still leads the way in blocking its implementation.

As The New York Times reported on its website Wednesday: "The Obama administration, grappling with continued political fallout over its health care law, said Wednesday that it would allow consumers to renew health insurance policies that did not comply with the new law for two more years, pushing the issue well beyond this fall's midterm elections."

And: "The reprieve was the latest in a series of waivers, deadline extensions and unilateral actions by the administration that have drawn criticism from the law's opponents and supporters, many saying President Obama was testing the limits of his powers."

Indeed, the administration's proliferating postponements and other changes to the law by executive fiat induce negative side-effects beyond the nation's medical system.

Like it or not (and we don't), both chambers of Congress passed the misnamed Affordable Care Act, albeit without a single Republican in the Senate or House voting "yes" and with 34 House Democrats voting "no." President Obama then signed the bill into law on March 23, 2010.

However, that law has been repeatedly altered by the president - without congressional consent.

That hasn't just stirred costly confusion among the business community and the general public. It has raised serious concerns on both sides of the political divide.

Jonathan Turley, a high-profile law professor at George Washington University, told the Times of this week's White House edict on the ACA: "I support national health care, but what the president is doing is effectively amending or negating the federal law to fit his preferred approach. Democrats will rue the day if they remain silent in the face of this shift of power to the executive branch."

And that day could come if a future Republican president uses this Democratic president's precedents of ignoring Congress' rightful role.

Yes, past presidents from both parties have tested the reach of their authority.

Yet Prof. Turley warned last week in testimony to the House Judiciary Committee: "I believe we are now at a constitutional tipping point in our system."

And this president hasn't confined his executive-order excess to picking and choosing which parts of the health reform law to follow.

More from Prof. Turley's testimony: "For example, when President Obama unilaterally acted on greenhouse gas pollutants, I was initially relieved. I agree entirely with the priority that he has given this issue. However, it takes an act of willful blindness to ignore that the greenhouse regulations were implemented only after Congress rejected such measures and that a new sweeping regulatory scheme is now being promulgated solely upon the authority of the president."

And it takes an act of willful power-grabbing for a president to usurp the legislative branch's proper authority with such flagrant regularity.

As a former constitutional law professor, President Obama should know better.

So as federal lawmakers sworn to uphold the Constitution, members of Congress from both parties should give the president a checks-and-balances refresher course.