At last common sense has prevailed both in Washington and in Ankara as sides have started to see the virtue of cooperating in earnest on Syria and northern Syria, and with the fanatics of the Islamic State of Iraq and al-Sham (ISIS) in particular.For a long time certain circles inside Turkey and outside the country have been trying to create an image that Turkey's government, which is regarded as devout Sunni Muslim, has been helping ISIS fanatics under the counter and thus bolstering them morally and materially. Of course all that was wrong. Yet they played the card that Turkey had initially supported the opposition groups in Syria and thus helped ISIS to flourish. Of course that was all wrong because other countries including the United States helped the Syrian opposition in good faith and no one expected a fanatical entity like ISIS to emerge and undermine the opposition efforts and wreak havoc.The mess created in northern Syria started with Bashar Assad trying to take revenge against Turkey and Recep Tayyip Erdoğan for turning their back on him and ordered his forces to vacate their positions in northern Syria and allow the Kurdish militants of the Democratic Union Party (PYD), which is an extension of the PKK that has created havoc for two decades in Turkey with its terrorist attacks, to advance. The PYD however, proved too weak for ISIS, who ran over the PYD-held areas and unleashed their own form of terror on the local people. The Americans leading the coalition force started bombing ISIS targets to keep the radicals at bay.The turning point came when ISIS tried to grab the Kurdish town of Kobani in northern Syria just across the Turkish border. At the time both Turkey and the U.S. were talking along the same lines saying aerial bombardments are not enough and land forces are needed to flush out the ISIS radicals. Turkey helped the Kurds of the PYD, allowing Iraqi Kurdish peshmerga forces to use its land to enter Kobani from Turkish soil and also provided other assistance including logistical support. The coalition jets hit ISIS repeatedly and forced them to retreat.Then the Syrian Kurdish forces of the PYD started to expand their territory and move into territories controlled by ISIS, but in the process became a threat to other groups like the Arabs and the Turkmens and even Kurds who do not ideologically think like them. The PYD also started to act as if it wanted to grab the whole of northern Syria and reach the Mediterranean Sea.That is where Turkey had to step in and serve notice to the PYD as well as the Americans that if the PYD moved west of the Euphrates River this would be unacceptable to Turkey and Ankara would intervene. Ankara also served notice to ISIS that its patience was running out as ISIS was threatening Turkmens, Arabs and Kurds irrespective of the fact that this is the holy month of Ramadan where the messages of peace and compassion of Islam should prevail. The PYD leader Salih Muslim secretly came to Turkey and Ankara served notice about its red lines.Ankara also hosted a high-powered American delegation on ISIS and the sides decided to step up their cooperation to finish off the radicals. Both sides were involved in frank discussions for two whole days and at last have started to see eye-to-eye on Syria in general and northern Syria in particular.The Americans and Turks agree that you need a fighting land force to counter ISIS in Syria. Now the sides seem to understand the limitations of the use of the PYD for this mission. Putting aside all the speculation of what kind of cooperation they will undertake, it is clear that Americans have seen you cannot go too far without Turkey and Turkey has come to grips with the idea that without American involvement the mess in northern Syria cannot be sorted out.