The United States is coming under increasingly bitter criticism for its perceived lack of leadership over Syria as the country's brutal civil conflict heads toward new levels of intensity.
Washington appears unable or unwilling to prevent its ally Turkey from bombing Kurdish fighters inside Syria, its critics say. And it has done little to rein in Russia's mounting military involvement on behalf of Bashar al-Assad.
In the eyes of his detractors, President Barack Obama is guilty of refusing to engage in Syria by doing exactly what he said he would do when he was elected in 2008: pulling America out of Middle Eastern wars, after the Iraq debacle, and "pivot" US foreign policy towards Asia.
A pointed attack came Tuesday from France, where few have forgotten Obama's last-minute refusal to take action against Syria in 2013 after evidence surfaced that the government used chemical weapons against civilians.
"Obama had said, 'If he uses chemical weapons, it will cross a red line," former Foreign Minister Laurent Fabius said Tuesday on Europe 1 Radio. "And that red line was crossed with no reaction."
"When the history books are written, we'll see that this was a turning point, not only in the Middle East crisis but also for Ukraine, Crimea and the entire world," Fabius had said earlier this month, adding that he regretted the "ambiguities" and "lack of very strong engagement" Washington has demonstrated with respect to Syria.
After the bombing of hospitals and other civilian targets around the northern Syrian city of Aleppo on Monday, the State Department only bemoaned the "continued brutality of the Assad regime against its own people" and questioned Russia's "willingness" to put a stop to it.
For Jonathan Schanzer of the Foundation for Defense of Democracies in Washington, that simply wasn't enough.
"Historians will one day look back at our archives and wonder what we thought we'd accomplish with such statements," Schanzer tweeted Tuesday.
The White House has dismissed the accusations of inaction.
Washington says the military coalition of 65 countries it has led for the past 18 months has carried out thousands of air strikes against jihadists of the Islamic State group, who control territory in both Syria and Iraq.
At the same time, Secretary of State John Kerry -- a skeptic of military interventionism known for his boundless public optimism about the diplomatic process -- has spearheaded an attempt to launch a peace process together with 20 global and regional powers.
The United States and Russia agreed in Munich on Friday on a "cessation of hostilities" in Syria within a week with the aim of relaunching the peace process and halting the exodus of civilians.
They also agreed to open humanitarian aid corridors.
But with Moscow intensifying its air campaign in northern Syria and Turkey stepping up calls for a ground offensive, any hope for a truce seems increasingly illusory.
US National Security Advisor Susan Rice condemned Monday's bombing -- most likely Russian -- of hospitals in Aleppo that left 50 dead, according to the United Nations.
"We think it runs counter, frankly, to the commitment made in Munich on Friday," she said, "and to our shared interest in seeing the violence reduced, civilians allowed to receive humanitarian assistance."
She also criticized Turkish air strikes against Syrian Kurds that are both poisoning relations between Moscow and Ankara and undermining the Turkish-American alliance.
Even Washington's critics understand it is in a very difficult position.
An ally of Ankara within NATO and the anti-terror coalition, it also supports Kurdish militia groups fighting ISIS in Syria.
The United States is also formally Russia's partner in the search for a political solution in Syria.
Kerry hashed out Friday's Munich agreement together with his Russian counterpart Sergei Lavrov.
However, few believe anything will come of it.
"One shouldn't expect anything from the Americans... They have no more credibility" in the Middle East, said Joseph Bahout, a scholar at the Carnegie Endowment who spoke Thursday just before the agreement was announced.
And in a recent article from the Brookings Institution, experts Michael Ignatieff and Leon Wieseltier argue it is "past time to proclaim the moral bankruptcy of American and Western policy in Syria."
"Western inaction," they write, is the result of "five years of empty declarations that Syrian President Bashar al-Assad must go, of half-hearted arming of rebel groups, of allowing the red line on chemical weapons to be crossed and of failing adequately to share Europe's refugee burden as it buckles under the strain."