Until this week, Turkey was an obvious candidate to join a coalition against Islamic State that includes Egypt, Iraq, Jordan and Lebanon.Turkey’s inclusion made sense. The country is, after all, a member of NATO. During the NATO summit in Wales last week, US President Barack Obama managed to rally support for a protracted war on Islamic State. It seemed that NATO – and Ankara – was on board.It is also seemed to be a Turkish interest to battle Islamic State. The Turkish border with Syria and Iraq is longer than 1,000 kilometers. Islamic State’s terrorist attacks have directly affected Turkey. Turkish news media have quoted members of the organization threatening to stage attacks within the country. An estimated 1,000 Turks have joined the group in Syria. Islamic State is making millions of dollars from selling fuel on Turkey’s black market. And Islamic State has taken hostage more than 40 Turkish diplomats and their families in Mosul, Iraq.Some Turkish officials claim that fear for the hostages’ lives is preventing Ankara from joining the anti-Islamic State coalition. In our view, the terrorist organization’s aggression against Turkey underlines the threat it presents and gives the Turks all the more justification for joining the fight.Nevertheless, Prime Minister Ahmet Davutoglu has made it clear he will not do so. Why? Ankara has not been behaving like a Western ally for some time now, despite its NATO membership. The country has been openly hostile to the US. It has permitted Islamists such as the Nusra Front – the al-Qaida affiliate in Syria – to move arms into Syria from Turkey. Ostensibly, this was based on the thinking that any enemy of Basher Assad’s regime was a friend of Turkey.Ankara must have realized that the jihadists using Turkey as a launching ground were staging attacks in Iraq as well. Even now, after the Islamic State threat has become a rallying cry, the Turks have refrained from cracking down on members of the terrorist group operating inside their borders.The only ones fighting Islamic State inside Turkey seem to be the Kurds. Revealingly, when Turkish police announced anti-terrorism raids, they targeted not Islamic State but the Patriotic Revolutionary Youth Movement, a group affiliated with the Kurdistan Workers Party (PKK).In contrast, Israel, a true ally of the West and of the US, is more than willing to cooperate with Muslim nations in the fight against Islamic State. Unfortunately, the US and the West seem to be wary of allowing Israel to openly join the coalition, for fear it will offend the sensibilities of Muslim nations that have come on board. Washington might accept Israeli intelligence; Israel has supplied the Americans with information from its spy satellites and travel databases. But no open cooperation is encouraged. Even the intelligence is scrubbed of any Hebrew or other markings that identify it with Israel, to avoid “raising hackles among Arabs,” Reuters reported.And while Defense Secretary Chuck Hagel and Secretary of State John Kerry have repeatedly tried to court Ankara – humbling themselves in the process – conspicuously missing was a parallel visit by Hagel to Israel as part of the coalition building effort.Some compare the Obama administration’s omission of Israel to a similar tactic used by president George W.Bush as he built a coalition against Saddam Hussein in 1991 after the latter invaded Kuwait.We would have thought, however, that after 9/11, after the concerted battle against al-Qaida and other Islamic extremists, the US and the West in general would appreciate that Israel is a true ally facing the same threat. Muslim animosity toward the West is not the product of colonialism, rapacious foreign policy or any other purported crimes perpetrated by the latter.Terrorist attacks such as 9/11, the 7/7 London bombings, and the 2004 Madrid bombings are motivated by hatred for all that the West represents – freedom, liberty, secularism. Anything short of repudiation of these values and the embrace of Islam will fail to satisfy violent Islamists. Caving in to Arab nations’ demand to keep Israel out of the coalition against Islamic State will not endear the US and other Western nations to the Muslim world. If will only encourage more bullying.Turkey has no qualms about standing up for what it sees as right. Western countries should not have any either.