Re: @Mark 85
"What's more, as Afghanistan showed before, and Syria and Iraq showed more recently, an unstable state breeds violence and terrorism."
The instability in the case of Iraq and to a lesser extent Syria comes from the old favourite in the ME, factionalism, and most of it can be placed squarely at the feet of the colonial powers who drew the lines in the sand post WWI based on their own post war settlements and with little regard to demographics. To be fair, they also in turn inherited a Sunni minority administrative class in Iraq from the Ottomans, and the pragmatic British happily kept them in power at the expense of the Shia. In Syria it was the even more minority Alawites that ended up at the top of the pile.
The leaders changed, but for the rest of the twentieth century the British and US simply backed whoever they felt was 'their bastard' of the day; as long as the oil flowed and the encumbent did pretty much what he was told on wider middle east policy with respect to the Soviets, he'd be well enough armed to slaughter Shia and Kurds as he liked. In doing so they just spent a century building a powder keg that erupted with Bush and Blairs vain project. When they handed the oil to their mates and a slice of power to the Shia and Kurds - and specifically pissed on the Baathists sense of self entitlement, the Sunni threw their toys out of the pram with a vengeance, and that rather than simple instability is the root of the current problems. The well trained and disciplined elements of the Iraqi military, specifically the Republican Guard allied with a growing number of Islamists spent the next decade making life hell for everyone, including the British and Americans.
When Syria started coming apart, they moved across the border and made good use of the captured Syrian heavy weapons that fell to the various opposition forces, and as ISIS, have been using that training and combat experience to good effect, turning what would have been a rag tag of factions as happy to slit each others throats as fight any nominal 'enemy' into a more unified, well armed force with a decent grasp of tactics, excellent knowledge of the terrain, a reasonably common ideology and considerable motivation, a loathing of 'different' and something very much like a plan that appeals to muslim populism; restoring the caliphate. The successes have brought more recruits and the know how to create a solid media strategy and plenty of funding - the Saudis are responsible for the core ideology and have been spreading it around the world for decades, providing plenty of well funded fertile ideological ground for recruiting. ISIS are also keeping Western countries at arms length by attacking them on their own territory, something of enormous additional symbolic value.
This is indeed instability, but its instability built layer by layer over decades of myopic Western and Russian foreign policy making that refused to look any further than immediate political and economic gains and ascribed values to people who had no interest in them, refusing to acknowledge natural boundaries or justice, or to participate in the building of stable states based on demographic lines long ago.
The only thing that has a passing chance of stopping this lot before they really do get entrenched are the the Kurds and in particular, the Shia, and not just those in Iraq. If the Americans really want to at least contain ISIS, they're going to have to do some hard thinking about their relationship with Iran (another problem of their own devising, long before Khomeini), and whether their bitter historical stance is now a bit past its sell by date in the current circumstances. It may stick in the throat, but the same applies to the view of Assads Syria, at least in the short term, and they could do a lot worse than reading the riot act very loudly to the Saudis. By the same token all European governments should immediately ban the Saudi funding of mosques in Europe, and deny visas to the Saudi trained and supplied Imams that dominate.
It may seem morally wrong and politically unsaleable in the US and Europe to come to an an accommodation with Iran (and through them Hezbollah in Lebanon) and Assads Syria, but almost no one, state or individual, beyond ISIS themselves and some elements in Saudi, want to see an entrenched Islamic state dominating the Middle East and taking their fight and absolutist ideology to states in and beyond the region. But unless Europe and America in particular do some rapid re-evaluation and swallow a lot of historical prejudices, that's exactly what they're going to get.