Press Secretary Jay Carney calls Assad's proposal for a new constitution that keeps him in power "laughable." Daniel Serwer analyzes the gambit:

[O]nly someone completely out of touch with what is going on in his own country could imagine that this initiative, prepared behind closed doors, would calm the situation so that a referendum could be held in less than two weeks.  Even the two-(seven-year) term limit on a given individual’s tenure as president is hardly a concession, since Bashar was "re-elected" in 2007.  The notion that Syrians are going to tolerate another two or three years of him is, well, bizarre.

That said, this is perhaps the first real sign that the regime is feeling pressure:  from the Russians, from the Arab League and perhaps from internal dissent.  To admit the possibility of actually leaving office–if only several years hence–is not going to satisfy anyone, but it goes farther than Bashar has been willing to go in the past.