At this point, the nature of that response is a mystery to no one.
A fifth US Navy destroyer with 300 Marines on board joined four warships positioned in the Eastern Mediterranean, "ready to go," according to US Defense Secretary Chuck Hagel, should the president give the order. On Saturday defense officials said that a sixth destroyer had joined the five already in the Mediterranean as a precaution. "It is not in the national security interest of the United States to ignore clear violations of these kinds of international norms," Obama said on Friday. "A lot of people think something should be done, but nobody wants to do it."
Yet, after a week of strategic leaks from US government officials indicating that an allied strike against Syria was imminent, Obama's indecision or delay has already produced some unintended consequences for the White House.
Out of step with the cautious, incremental approach to foreign policy that has become his hallmark, the president dramatically charged Syrian President Bashar Assad last week with crossing an uncrossable American red line, deployed forces and shook alliances awake from a comfortable slumber on the Syrian crisis, now well into its third year.
The president's goal was to quickly build an international consensus that would not only condemn Syria's Assad for using chemical weapons on a massive scale on August 21 in the Damascus suburb of Ghouta. He also wanted to build a formidable coalition that would join the US in a military strike, meant to send a principled message that the use of chemical weapons cannot be tolerated.
From the Treaty Room of the State Department on Friday, Secretary of State John Kerry laid out the case for action, presenting a declassified intelligence report and warning that inaction in and of itself was a fateful choice.
"This crime against conscience, this crime against humanity, this crime against the most fundamental principles of international community... this matters to us," Kerry said. "And it matters to who we are. And it matters to leadership and to our credibility in the world."
But that message first began eroding Thursday night, as Britain's Parliament shocked the White House by voting against joining a military strike. British leader David Cameron had already sent two warships to the Eastern Mediterranean and six fighter jets to Cyprus.
Following the vote in London, The Washington Post published an article Friday morning claiming rampant skepticism among top military brass at the Pentagon, worried that the Syria operation does not have clear aims and might aggravate the situation on the ground.
The article mostly quotes retired military officials, but supports sources of The Jerusalem Post who claim that the president experienced "pushback" on the possible use of force last Wednesday.
“There’s a broad naivete in the political class about America’s obligations in foreign policy issues, and scary simplicity about the effects that employing American military power can achieve,” retired Lieutenant General Gregory S. Newbold told The Washington Post, noting that his contemporaries are "alarmed" by the plan.
Then, on Friday, as Kerry and Obama continued making their case for humanitarian intervention and the protection of international standards of decency, a new Reuters/Ipsos poll suggested that a majority of Americans still oppose any military involvement in the Syrian crisis. The numbers have shifted, however; 53 oppose intervention now, down from 60 percent a week ago, and 20 percent are now in favor, up from 9 last week.
The White House plan seems to be backfiring: instead of growing an international consensus and a broad military coalition, the administration is instead facing mounting pressure and tougher questions the more time passes from that fateful day in Ghouta, when over a thousand civilians were killed in the dead of night by weapons that leave no flesh wounds.
Crisis in Syria - full JPost.com coverage
Obama has already managed to coalesce Turkey, Jordan, Australia, Canada, Germany and the Arab League into agreement that the Assad regime is culpable for the attack, and that his use of chemical weapons on a mass scale demands a strong international response. But the likelihood that any of those nations will join a military effort is unlikely, save for perhaps Turkey, whose leader has been highly critical of Assad throughout the war.
"We are not alone in our condemnation, and we are not alone in our will to do something about it and to act," Kerry said on Friday.
Obama faces a difficult timeline for a strike going forward, should he choose to proceed with French President Francois Hollande, who says his country remains committed to the cause of deterrence.
UN inspectors left Damascus on Friday, giving Obama four days to strike before he arrives in St. Petersburg, Russia, for the G20 Summit. He will travel to Sweden beforehand on Tuesday night. If he does not strike before then, the pressure to refrain from the summit's host, Vladimir Putin, could be extraordinary.
The military campaign could last for several days, officials say.
Next Wednesday also marks the high holy day of Rosh Hashanah on the Jewish calendar, which could complicate an attack due to threats from the Syrian and Iranian regimes to retaliate against Israel for any Western strike. Threatening a surprise attack, Syria's foreign minister this week invoked Arab tactics against Israel in the Yom Kippur War.
A week later, the US will mark the twelfth anniversary of the 9/11 attacks.