There are fixed dates in the law. These are not mere suggestions, or gentle hints. They are not subject to executive modification.
Obama is failing to faithfully execute the laws and therefore is violating his oath of office.
This is the most fundamental impeachable offense.
I don't disagree, but the Republicans must make an articulate and cogent case against him before uttering the word "impeachment" in the House of Representatives. And while they don't have to convince everyone, they must at least cause people to raise their eyebrows, and maybe even get a few lime-minded Democrats on their side. Otherwise, the GOP looks petty.
I say this, not in defense of Obama, but because I recognize that impreachment is more a political thing than a legal one. One need only look back as far as Bill Clinton, to see that. People wanted to give him the benefit of the doubt--remember, "it's not really an impeachable offense if the economy's doing great, right?" What sort of benefit would Obama get?
You can bet that Obama's defenders will argue and mince words, using logic like, "he had to bend the law, in order to enforce the law!" Or, "he's using effective project management skills to adjust the enforcement timing." And until the Republicans can get more that Fox News to report a story accurately, or until they get film of Obama in a hot tub with a 14 year-old boy, they're only going to look silly. If they couldn't make the events in Benghazi stick, they're not going to make "failure to faithfully execute laws" to stick.