Will Turkey join the fight against ISIL?

Reluctant no more, Ankara says it is changing its approach to the radical group. The Turkish President, Recep Tayyib Erdogan, says his country is willing to join ground operations to protect refugees from the Islamic State of Iraq and the Levant. He says the Turkish parliament is expected to vote on October 2 on whether to authorise the army to conduct cross-border operations in Iraq and Syria. Iran, another regional power, is mulling its options on how to deal with ISIL. President Hassan Rouhani said at the UN that if a long-term deal on its nuclear programme is reached, Tehran will co-operate with neighbouring countries to fight what he described as extremism. Saudi Arabia, deeply involved in the campaign against ISIL, has publicly expressed concerns over Iran's possible involvement. So, what are the politics that drive regional powers in how they deal with the ISIL threat?