"Earlier this week, one Iraqi cried that there is no one coming to help. Well, today America is coming to help," Barack Obama said last night. In response to the threat posed to the Yazidi minority, besieged on Mount Sinjar after being pursued by Islamic State (IS) jihadists, the US president has authorised air strikes to prevent what he described as a potential "genocide".
"When we face a situation like we do on that mountain, with innocent people facing the prospect of violence on a horrific scale and we have a mandate to help - in this case a request from the Iraqi government - and when we have unique capabilities to act to avoid a massacre, I believe the United States cannot turn a blind eye," he said in an address from the State Dining Room of the White House.
For the first time since its troops withdrew from the country at the end of 2011, the US has returned to a military role in Iraq. But Obama emphasised last night that "As commander in chief, I will not allow the United States to be dragged into another war in Iraq".
Where does the UK stand? The government has welcomed Obama's decision, while emphasising that "we are not planning a military intervention" (which is not quite the same as ruling it out). After being defeated by MPs over intervention in Syria last summer, and with a general election just nine months away, Cameron is wary of engagement. But he has asked officials to establish "what more we can do to provide help to those affected, including those in grave need of food, water and shelter in Sinjar area."
He added: "I welcome President Obama’s decision to accept the Iraqi Government’s request for help and to conduct targeted US airstrikes, if necessary, to help Iraqi forces as they fight back against ISIL [sic] terrorists to free the civilians trapped on Mount Sinjar. And I fully agree with the President that we should stand up for the values we believe in – the right to freedom and dignity, whatever your religious beliefs."
Given the UK's role in the 2003 invasion, widely blamed for the sectarian strife in Iraq, some MPs argue that the government has a moral obligation to act. Mike Gapes, a Labour member of the foreign affairs select committee, and its former chairman, tweeted: "Why is weak Cameron ruling out UK support for @KurdistanRegion in exisential fight v ISIL terrorist butchers? Contrast Major 91."
But in the absence of a sudden change of heart in Downing Street, it looks likely that any UK involvement will be strictly non-military.