The Scottish writer William Dalrymple says that Syria has been a kind of oasis for Christians in the  Middle East.  But Syrian Christians are now faced with a painful choice. They can offer support to a brutal dictatorship that, generally, has protected them but has killed 5,000 of its citizens since calls for change and demonstrations began in the spring of 2011. Or Christians can participate in the opposition, which, if it topples the regime, may bring to power a Sunni-led government that could be ultra-conservative and anti-Christian.