Turkey – from reluctant observer to full player in IS fight -BBC

Within a week, it has gone from a reluctant observer, abstaining from military action against so-called Islamic State, to full-blown military strikes against the group, opening up its bases to coalition attacks and, simultaneously, the first aerial bombing of PKK Kurdish separatists in northern Iraq in four years.

Why the sudden turnaround?

http://www.bbc.com/news/world-europe-33664269