UPDATE(s) – As predicted earlier today: Harry Reid has cancelled Senate vote authorizing President Obama to take military action.   AND President Obama backs off Red Line and says he’s open to “diplomatic tack”.
The reasons WHY are evidenced as they were previously outlined below:

After 10 straight days of pressure from President Obama’s team, the request for congressional authorization is failing miserably.    All intellectually honest DC operatives, pundits et al, are all in agreement any vote in House of Representatives would fail horridly, and passage in the Senate is doubtful at best.
President Obama will not allow a vote call upon either chamber that he knows would fail.  [Unless, of course, the vote failure was to his benefit – that’s not the case on this Syrian authorization].  Harry Reid will not call a vote in the Senate which would embarrass or humiliate President Obama.
That said, now the issue becomes how to get President Obama out from his self inflicted plunge under his own bus.   This phrase, which will eventually come from the mouth of Obama, is what all political efforts are working toward:

“I was never for militarily attacking Syria, I always wanted a peaceful solution”.

Obama needs to position himself as being reluctantly dragged toward conflict now.  He needs to make the case that *HE* did not want to attack Syria, the global demands of humanity were forcing him to threaten Assad.
President Obama needs a soft landing to save face – to find a soft landing you need to receive a ‘soft message’ from your adversary.   Russia knows this.
Russia and Syria know there is no popular support for Obama.  Russia knows from decades of experience inside the U.S. exactly what the internal public opinion does to any administration;  and most importantly Russia knows what is described above as to what POTUS protectors are doing to safety net President Obama.   Hence….  
MOSCOW — Syria on Monday quickly welcomed a call from Russia, its close ally, to place Syrian chemical arsenals under international control, then destroy them to avert a U.S. strike, but did not offer a time frame or any other specifics.
The statement by Syrian Foreign Minister Walid al-Moallem appeared to mark the first official acknowledgement by Damascus that it possesses chemical weapons and reflected what appeared to be an attempt by Syrian President Bashar Assad to avoid the U.S. military attack.
But it remained to be seen whether the statement represented a genuine goodwill gesture by Syria or simply an attempt to buy time.
“Syria welcomes the Russian proposal out of concern for the lives of the Syrian people, the security of our country and because it believes in the wisdom of the Russian leadership that seeks to avert American aggression against our people,” al-Moallem said during a visit to Moscow, where he held talks with his Russian counterpart, Sergey Lavrov.
However, al-Moallem, would not give any further details in his brief statement and didn’t take any questions from reporters.

Moallem’s statement came a few hours after U.S. Secretary of State John Kerry said Assad could resolve the crisis surrounding the alleged use of chemical weapons by his forces by surrendering control of “every single bit” of his arsenal to the international community by the end of the week.
Also Monday, U.N. Secretary-General Ban Ki-moon urged Syria to immediately agree to transfer chemical weapons and chemical precursors to a safe place within the country for international destruction.  (read more)