Arming Syria’s rebels is a gamble.
It might even the battlefield odds.
Just as easily it could ignite an explosive arms race.
That’s only one of the risks Britain and France run in forcing the EU to abandon its ban on shipping weapons to Syria in the hope it’ll force President Assad to the negotiating table.
To illustrate the point, the immediate response came not from Damascus but from Moscow.
Russia announced it would go ahead with the supply of an advanced air defence system to its Arab ally to deter what the deputy foreign minister called "hotheads’’ determined to intervene.William Hague will have got the none too subtle message.
In turn, the Moscow missiles sent sent alarm bells ringing in Israel; which has for many months urged the west and western weapons to stay out of Syria for fear those armaments could one day be turned on Tel Aviv or Jerusalem.
But the Russian missiles are a threat of another order, Israel’s intelligence minister Yuval Steinitz warned today; imagine what would happen if they came into the possession or Hezbollah or Iran, he urged.
Even more urgently, he was probably imagining what the missiles might do to Israeli warplanes attacking targets in Syria, as has happened three times this year.
It’s not yet clear when Britain might begin to supply guns; nor what limits it is placing on the size of the armaments, nor how weapons will be kept from the hands of hardline Islamists now dominating the opposition.
The Syrian war has already spilt over its border and spilt blood in clashes in Lebanon while missile and mortar rounds have landed in Israel.
A peace conference planned next month is being invested with a great deal of hope; but far less expectation of success.
It is hard to see the mere threat of supplying arms to the Free Syrian Army changing the dynamic.