WASHINGTON (AP) - State Department officials shook up America's generally obedient diplomatic establishment this week with an internal memo urging U.S. military action against Syria's government with the goal of pressing President Bashar Assad to accept a cease-fire and gaining the upper hand on him in future talks on a political transition.
Reasons abound for why an intervention is improbable, not least the vague military objective and risks for U.S. service personnel. Most significant, President Barack Obama is opposed.
Even the diplomats who signed the "dissent channel cable" aren't calling for U.S. forces to push Assad out of power immediately or make him surrender territory to opposition groups - more typical goals for military campaigns. Instead, they say targeted U.S. attacks could increase leverage over the Syrian leader in diplomatic negotiations that have repeatedly failed so far.
Intervening would plunge Washington into an unpredictable and deadly conflict. The Syrian opposition includes scores of rebel formations jostling among rival ethnic groups and U.S.-designated terrorist organizations such as the Islamic State. Russia's air force, Iranian troops and paramilitary units are fighting alongside Assad, crowding the skies and the battlefield.
American priorities are elsewhere. Despite calling on Assad to step aside five years ago, Obama is focused on defeating the Islamic State in Syria and not regime change. His administration wants to preserve Syria's state and army for a future "transition government" that could restore order and help tackle IS. It wants Russia and Iran to help in that effort.
Here is a look at what frustrated State Department officials called for and why a policy shift is unlikely:
WHITE HOUSE RESISTANCE
The now classified cable was transmitted through an official channel for dissenting views. Fifty-one mostly mid-level department officials who work on America's Syria policy signed on. The New York Times and Wall Street Journal quoted from copies they reported seeing or obtaining.
The document expresses clear frustration with a White House-driven response to a conflict that has killed perhaps a half-million people and contributed to a worldwide refugee crisis.
"The moral rationale for taking steps to end the deaths and suffering in Syria, after five years of brutal war, is evident and unquestionable," the Times quoted it as saying.
The sentiment isn't new in Foggy Bottom. Obama's last two secretaries of state pushed for intervention, as has a former defense secretary and CIA director. However, the commander in chief has the last word, and nothing has swayed him thus far.
When Assad crossed Obama's "red line" in 2013 by using chemical weapons, the U.S. president backed down from his threat of retaliatory strikes. And ongoing chaos in Libya, where the U.S. helped overthrow dictator Moammar Gadhafi in 2011, is only making him more reticent.
MANY UNKNOWNS
Apart from defeating IS, Obama's Syria strategy has three stages: forcing Assad into a cease-fire and "political transition" talks, pressing him to leave power, then uniting his army and moderate forces to join the counterterrorism effort.
After five years of civil war, the chain of events hasn't yet started. Fighting rages despite numerous partial cease-fires between Syria's government and opposition groups.
Also, without leverage, the dissenters noted, Assad will never feel pressure to stop bombing and negotiate.
Military action can "drive a more focused and hard-nosed U.S.-led diplomatic process," they said, shifting "the tide of the conflict" and sending a "clear signal to the regime and its backers that there will be no military solution."
However, if airstrikes are limited, would they scare Assad into peace talks or make him more determined to dig in? If the U.S. ultimately hopes Assad will negotiate his own departure, what new incentive would he have?
"The threat of strikes brings dramatic results," Andrew Tabler, a Syria expert at the Washington Institute for Near East Policy, said approvingly of the memo. "This isn't about invading Syria or another Iraq. It's about punishing Assad for his violations of the cessation of hostilities. And it could, if backed up with resolve, change Assad's increasingly rigid negotiating position."
The memo says doing that would address the lack of support among Syria's Sunni majority for the U.S. goals of isolating and defeating IS. Sunnis are leading the fight against Assad, a member of Syria's Shiite-linked Alawite minority.
RUSSIA
"We have been arguing from the beginning of the Syrian crisis that there should be more robust intervention," Foreign Minister Adel al-Jubeir of Saudi Arabia, a key U.S. ally, said Friday.
However, if planning an intervention was complicated early on, it became harder after Russia's foray into the conflict in September.
Attacking Assad's forces now would risk escalating a proxy war with Moscow, which has been hitting U.S.-backed rebels. The prospect of accidental confrontation grows if the two militaries end coordination on avoiding each other's forces in their separate counterterrorism campaigns.
The dissenters acknowledge these risks, but say Russia, too, must be serious about halting violence and negotiating a political transition.