US airstrikes against the terrorists of Islamic State have expanded into Syria.  The move was widely expected, although some observers expected it to begin after the UN Summit in New York City.  The timing suggests that world leaders attending the meeting, including Prime Minister Tony Abbott, will have to go on the record on whether they approve or disapprove, whether they will or will not take part.

US forces are targeting at least twenty sites included Islamic State's command and control, supply, militant housing, and training facilities.  The Americans are deploying bombers and fighter jets (including B-1, F-16, FA-18 aircraft), which will be followed up with a barrage of Tomahawk missiles from nearby carriers and guided missile cruisers in the Red and Mediterranean Seas.  

The airstrikes were not invited by the Syrian government, and Russia had cautioned other countries not to violate Syrian sovereignty.  It's not clear how Syrian President Bashar al-Assad will respond to this, as his forces wage war against rebels that include so-called moderates backed by the west, al Qaeda-linked al Nusra front fighters, and Islamic State - the terrorist group so violent and vile that al Qaeda renounced it.  Assad's anti-aircraft batteries are far away from Islamic State's strongholds around Raqqa in the east of the country, and it's unlikely that Assad will stop something that's helping him.