Should we obey the leaders who take Jews and Christians as their friends against Muslims?

We must obey those rulers who are Muslims, and they deserve our obedience. This is one of the principles of the 'Aqeedah of Ahl-us-Sunnah wal-Jama`ah. However, if you look at the majority of Muslim rulers in our day and age, the reality is that most of the rulers who are ruling the Muslim countries today and have ruled in the past, are not even Muslims even if they claim to be Muslims. An example of this is the former dictator of Libya Muammar al-Gaddafi. Shaykh Bin Baz, the former Grand Mufti of Saudi Arabia, declared him as a Kafir. Also, the current tyrant who is ruling Syria, Bashar al-Asad, comes from the extreme Shi'ah sect known as the Nusayri or 'Alawi sect which Muslim scholars consider to be outside the fold of Islam, and regarding whom Shaykh al-Islam Ibn Taymiyyah said, “The Nusayriyyah are worse in kufr than the Jews and Christians, and worse than many Mushrikun. Their harm upon the Ummah of Muhammad (ﷺ) is greater than the harm of Kuffar combatants.”

As for the other Muslim rulers, we cannot say that they are Kuffar until it is clear that they have done certain things or said certain things which take a person out of the fold of Islam, and until the conditions for declaring them Kuffar have been fulfilled and any preventive measures from declaring them Kuffar have been removed.

As for the question about allying with the Jews and Christians, then obviously, allying with Jews and Christians against Muslims is one of the things which takes a person out of the fold of Islam. Allah says,

“O you who believe, do not take the Jews and the Christians as allies. They are in fact allies of one another. And if any amongst you takes them as allies, then indeed he is one of them.”[1]

And Allah knows best.

Reference:

[1] [Qur’an 5:51]