EXPRESSIONS of outrage over the massacre at Houla in Syria echoed around the world over the weekend. From Hillary Clinton in Washington, to William Hague in London, and the UN security council in New York and of course from Syrian opponents of Bashar al-Assad, the words were powerful and condemnatory — commensurate with the wholescale killing of innocents, including 32 children.

But words are the easy part. And words can be qualified and mislead.

Russia, Assad’s most loyal ally, signed up to the UN statement (which notably failed to ascribe blame) while its deputy ambassador quickly added that the circumstances of the carnage were “murky”. Syria itself, defiant as ever, complained of a “tsunami” of abuse, as if it were the victim.

Agreeing a coherent and effective international response to the bloodiest crisis of the Arab spring is looking more rather than less difficult, despite levels of cruelty and depravity that will rank Houla alongside infamous killing grounds elsewhere.Responses so far suggest more of what has been tried and found wanting over the last 14 months: on top of a non-binding UN statement, there is talk of yet more EU sanctions; another meeting of the Friends of Syria group; a frosty few minutes at the UK Foreign Office for the Syrian charge d’affaires.

Two encounters might make a difference: Kofi Annan is meeting Assad on Tuesday to discuss what remains of the peace plan that bears his name. Six weeks on, the ceasefire remains a fantasy. Assad has yet to withdraw his forces from towns, let alone launch a dialogue with the opposition. Armed actions by the rebels of the Free Syrian Army and suicide bombings that have been blamed on Al Qaeda have made that even harder.

William Hague, meeting his opposite number, Sergei Lavrov, in Moscow, was seeking to persuade the Russians, in effect, to stop backing Syria. But is it likely that Lavrov will waive its veto and sign up to what the British call the “accountability track” — set in motion moves to refer Syria to the international criminal court for war crimes? And anyway, would it make any difference? It didn’t affect the Libyan regime last year.

Still, with evidence that the Syrian army used tanks and artillery against Houla — and that a Russian freighter docked in Tartous on Saturday, bringing in new weapons supplies — there might be some discomfort that could be leveraged into pressure on Damascus.

Annan and Hague are both exploring whether the “Syrian-led political dialogue” element of the UN/Arab League plan could be elided into a more explicit scheme for transition, borrowing the negotiated model that led to Yemeni’s Ali Abdullah Saleh stepping down — albeit while leaving much of his regime intact.

US officials were talking up that option over the weekend but it is hard to see why its chances should be any better than before.

Hanging over the whole bleak story is this unchanging truth: last year’s Arab-backed Nato intervention in Libya will not be replayed in Syria.

Every idea that has been suggested to help the opposition and weaken the Damascus regime, for example humanitarian corridors, no-kill zones, safe areas, would all require offensive military operations. Those are not on the cards.

Assad knows that.

Syria in 2012 is looking more and more like Bosnia 20 years ago: measures by the international community to mitigate the conflict either have little effect or actually make it worse. If 300 UN observers have proved ineffective, will 10 times that number be any better? Will Houla prove to be a defining moment? The bitter truth is that there may be many more such atrocities before anything much changes.

By arrangement with the Guardian