Tony Blair was in Sonoma County, California, this week to open an "industrial winemaking facility" as part of his role as senior adviser to a Silicon Valley firm called Khosla Ventures. How does he find the time to bring peace to the Middle East and promote all these excellent ventures, such as that methanol plant in Azerbaijan he turned up in in one of his shiny suits. Meanwhile Cherie Blair has been defending her half-sister's conversion to Islam by arguing: "There are thousands of Muslims in Europe who participate in our way of life and intend continuing to do so and if they want to dress in a certain way because of their beliefs, we shouldn't feel threatened." I agree, to an extent. But of course it's not just in Europe where niqabs have become fashionable in the past 10 years. There's this place her husband may have heard of called "Iraq", where people have had every right to feel threatened by the veil. For thanks partly to Tony Blair and his well-intentioned but ill-thought-out war, Iraq's indigenous Christian minority is, to put it bluntly, close to extinction. Before the US-led invasion the country's Christians, most of whom still speak Aramaic, numbered between 800,000 and one million; today fewer than 400,000 still live there, and following Sunday's massacre at a Catholic Church, where 58 people lost their lives following attack by Sunni militants, their chances of survival look more bleak than ever. Isn't it a fantastic achievement for this man of faith that, thanks to him, the language of Christ may soon die out? Not only have hundreds of Christians been deliberately murdered since 2003, but over 60 churches have been bombed. Can you imagine the (rightful) anger in the Islamic world if Christian fundamentalists were allowed to slaughter mosque-goers in Europe? The Baghdad church massacre didn't even trend on Twitter, and yet "British sausage week" did. If some Muslims despise the West and our frivolity, they have good reason to. Why should we care? Because the exodus of Christians from the Middle East is a massive disaster in the making for everyone, as their flight removes a moderating force from the Islamic world. Christians in the region have for centuries acted as bridge-builders between East and West. As they flee, the chances of future understanding between historically Christian and Muslim civilisations recedes. The vast majority of Iraqi Christians and Muslims live in peace with each other and have done so for hundreds of years, but in an unstable state it only takes a few nutters to create chaos and drive a community out. For that reason Iraq's Assyrian Christians (they're a different ethnic group as well as religion) have repeatedly called for an administrative unit in the Nineveh plains in northern Iraq, where they are most concentrated; this would be run and policed by Iraq's minorities (not just the various types of Christians but several other tiny, obscure and threatened groups like the Mandaens, who are followers of John the Baptist). The Assyrians maintain that without this protection they are doomed, but the Kurdish authorities oppose the plan, and so the Americans won't help. Following the Baghdad massacre, they'll be protesting in London this Monday at Noon, as part of a worldwide attempt to make the US and Europe listen. I'll be there; I hope you can be too.