When can a president change or ignore a law at will?

Let's review:  The Constitution says Congress is supposed to pass laws, and the president is supposed to enforce what congress passes.

But Barack Obama--according to the Lying Media a "professor of constitutional law"--has decided the Constitution is obsolete, at least insofar as it purports to tell him what he's allowed to do.  So in his vast wisdom, HE has decided he will decide what part of a written law he will enforce, and which he will simply change.

That is so cool!  Why should we have to wait while that plodding, worthless congress grinds out the details of amending a law when a president can simply settle things by decree?

With the stage thus set, I invite your attention to the graphic below:  Having rammed Obamacare into law, without allowing a single Republican amendment, Barack Hussein Obama has now seen fit to amend that law--by decree--so many times you've lost count.  (Not that the media was keeping track anyway.)

This is unconstitutional.  He should be facing impeachment and removal from office.  "Period."