Syria The UN security council cannot even agree on the wording of a statement condemning government violence. Russia says events in Syria do not pose a threat to global peace.
Libya The UN security council authorises "all necessary measures" to protect civilians in Libya. Council members pointed to support for a no-fly zone from the Arab League to justify the decision.
*Balance of forces
Syria Syria's armed forces are far stronger, thought to number 325,000 regular forces and more than 100,000 paramilitary. The elite units are drawn from the same Alawite minority as the Assad family. The ruling Baath party also has stronger ideological glue holding it together than the Gaddafi cult in Tripoli. There is no sign the protesters have taken up arms in any systematic way, and they hold no territory.
Libya Rebel forces had taken most of eastern Libya but were being driven back in disarray to their stronghold in Benghazi at the time the decision to intervene was taken. Gaddafi has a weak 50,000-strong army, but his paramilitary units proved more tenacious and better equipped. There were western hopes of mass defections in the armed forces and government in the face of UN, Nato and Arab resolve, but those hopes were thwarted. The regime held together and has continued to strike back.
*Threats to civilians justifying intervention
Syria Four hundred protesters are already thought to have been killed and a bloody crackdown is under way in Deraa. The regime and its security forces have a reputation for ruthlessness.
Libya At the time of the first French air strike on 19 March, civilian casualties were thought to be low. However, Gaddafi forces were on the outskirts of the city of Benghazi, and Gaddafi had warned that they would go from house to house and "show no mercy".
*Allies
Syria Syria has solid support from a major regional player, Iran, with fearsome armed forces and a readiness to project its force abroad. It has a strong relationship with Turkey, a Nato member. Damascus's longstanding ties to Hezbollah in Lebanon, and Hamas in Gaza, add another dimension to its possible reprisals against punitive measures.
Libya Gaddafi has enemies around the world, particularly in his own region. Western intervention would almost certainly not have happened if it had not been endorsed by the Arab League, and actively supported by a couple of Gulf states. Only Venezuela spoke out strongly in Gaddafi's defence, while Zimbabwe was one of the few states thought willing to give him safe haven if he stepped down.
*Regional impact of intervention
Syria Unpredictable but almost certainly serious and hard to contain. Proximity to, and enmity towards, Israel risks turning any outside intervention into another chapter in the Israeli-Arab struggle. Iran's alliance with Damascus and its willingness to take on the west by proxy, as it did in Iraq, is another risk. It would be likely to destabilise Lebanon, where Hezbollah has a close relationship with Syria and Iran.
Libya Limited. Libya has few friends and is sandwiched between two states that have undergone their own democratic revolution and had no sympathy for the Gaddafi regime. The Nato intervention was given credibility and political cover by Arab League endorsement, and there would have been Arab anger at a failure to intervene.
