First a ceasefire in Syria, then aid and then -- who knows -- perhaps a political transition? Don't bet on it, analysts warn, saying Washington has put too much faith in Moscow.
Efforts to end Syria's brutal five-year civil war may hang by a thread, but Washington's top diplomat will once again throw himself into the fray.
Secretary of State John Kerry set off on Friday for Saudi Arabia to consult with his Arab ally before talks on Syria in Vienna on Tuesday.
Once again, senior officials from the 17-nation International Syria Support Group (ISSG) will meet to reaffirm their support for peace.
But will they have any more success than they have had so far? Or will Bashar al-Assad and his rebel foes fight on as Syria drowns in blood?
"Obviously, not all the trend lines in Syria are going in the right direction," Kerry's spokesman John Kirby admitted on Friday.
"There's plenty of work to be done in the ISSG," he added. "And the secretary is still mindful of the challenges ahead."
But many of the US administration's critics think the plan is doomed by a fundamental flaw -- it relies on Russia's good graces.
- Regional paranoia -
Kerry and his Kremlin counterpart Foreign Minister Sergei Lavrov, the odd couple of great power diplomacy, are co-chairs of the ISSG.
Moscow has undertaken to pressure its ally Assad to respect the shaky truce that Washington hopes will smooth the path to political talks.
And the US, with regional ally Saudi Arabia, is working to reassure an opposition coalition that a ceasefire will lead to a political transition.
But what if, reassured by the military and diplomatic support of Russia and Iran, Assad and his regime have no intention of standing aside?
"Regardless of what the Russians might want, they are effectively supporting a victory operation on behalf of Syria and the Iranians," said Jim Jeffrey, a former top diplomat and senior adviser to president George W. Bush.
"And all we have against this is to meet with the Russians and plead with them to adhere to all of these agreements," he told AFP, arguing that Moscow has already backtracked.
"The Russians agreed to a clear political transition -- they have not delivered on that."
And it is not just former senior officials from Republican administrations who feel Kerry's Russian outreach will not be enough to dislodge Assad.
"Keep in mind we're not asking the regime to come to the table," said Philip Gordon, a former member of President Barack Obama's National Security Council.
"We're asking them not to exist. We're asking them to get rid of their leader," he told reporters this week at the Council on Foreign Relations.
Kerry's response to this obvious flaw in the ISSG strategy is to hope that Russia will grow tired of propping up its friend in Damascus.
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Gordon, Jeffrey and many others -- including serving diplomats from US allies speaking privately -- find this naive.
"I think many have consistently underestimated Russia's determination to prevent this regime from falling," Gordon said.
In Jeddah before the full ISSG meeting, Kerry will seek to reassure the Saudis -- and through them the Syrian opposition -- that Assad's days are numbered.
But it is not clear what will happen if he holds on beyond the supposed August 1 cut-off that the ISSG has agreed must be the start of a process of transition.
Obama, still proud of his record as the president who extricated the United States from Iraq, shows no sign of wanting deeper military involvement in Syria.
Earlier this year, Kerry publicly floated the idea of a 'Plan B' in which stepped up US and allied support for the rebels might give Assad pause.
But he has gone silent on that idea in recent weeks, and his spokesman refuses to address it.
"There is no plan B for Syria. It's a very different situation," snorted Jeffrey, now a fellow at the Washington Institute.
"These guys are on a roll and everybody in the Middle East notices this," he said of President Vladimir Putin's Russia.
Meanwhile, some observers suggest the overthrow of Assad should not be Washington's main target.
- Military options -
Gordon argued that the current position on the ground -- with Russian and Iranian forces defending Assad -- means any US meaningful intervention would be costly.
"It is perfectly legitimate to argue we should do whatever it takes," Gordon said of military options. "But let's not pretend it's a modest increase."
The US and its Saudi, Turkish and Gulf Arab allies could increase the scale and sophistication of arms in the hands of the rebels.
But without a large-scale US-led intervention -- one that the American public would likely not support -- Assad could cling to power indefinitely.
"If you are not prepared to do what I think would be necessary to do to achieve that political objective, then you have to change that political objective or accept that the war just goes on with all of these consequences," Gordon argued.
Instead of the Kerry plan -- which Kirby outlined as being to secure a truce, extend humanitarian aid and then begin a transition -- why not shift the focus off Assad?
Then, Gordon argued, if the ceasefire takes hold and people begin to see the benefits of peace, areas outside Assad's control may begin to develop self-governance.
Jeffrey, by contrast, called for a tougher stance.
He compared the Syria strategy to the relatively successful bid to freeze the Ukraine conflict by stepping up NATO's military posture and imposing sanctions on Moscow.
Would either plan work? No one can guarantee it. But nothing else has.