For reference, here is Obama's executive order to close Guantanamo (date: the 2 days after inauguration).

http://www.whitehouse.gov/the-press-office/closure-guantanam...

Just because he could convince congress to stop blocking him doesn't mean the concessions he would have to make would be reasonable. They probably wouldn't be as bad as Clinton/CHIP (Republican congress holding health care for children hostage to secure a 33% cut in capital gains tax during an economic boom), but if said history is any indication the concessions he would have to make to fulfill his mandate might cost thousands of American lives.

He could in the same way that the laws of physics don't prevent me from, I dunno, jumping off of a bridge or stealing a kidney from a homeless person.

To be fair, Larry didn't post that comment. It's written by an anonymous person who claims to have heard Larry say that.