Shaykh Bin Baz said, “…Seeking the help of unbelievers to ward off the evil of other unbelievers, aggressive Muslims, or Muslims expected to wage impending aggression is permissible.
It is authentically reported that the Prophet (peace be upon him) fought using shields he borrowed from Safwan Ibn Umayyah – who was unbeliever at the time – while fighting Thaqif in the Battle of Hunayn.
All the people of Khuza`ah, Muslims and unbelievers, were fighting with the Prophet (peace be upon him) while he (peace be upon him) was fighting against the unbelievers of Quraysh at the day of the Conquest of Makkah. It is authentically reported that the Prophet (peace be upon him) said: “You will make a peace-treaty with the Byzantines and together you will invade another enemy. You will be victorious and take much booty.”
This indicates the permissibility of seeking their help in fighting enemies beyond us. What is meant is that it is permissible to defend Muslims and their countries by Muslim or non-Muslim forces.
It is permissible to use their weapons or armies to help Muslims ward off aggression and protect their countries against the evils and intrigues of their enemies.
Allah (Glorified and Exalted be He) says in His Glorious Book: “O you who believe! Take your precautions.”
Thus, Allah (Exalted be He) orders us to take our precautions against our enemies.
Allah (Glorified and Exalted be He) says: “And make ready against them all you can of power.”
The same ruling applies to whosoever commits aggression against us, even if he was a Muslim or is associated with Islam. If Muslims fear aggression being committed against them, they can also seek the help of anyone whom they can seek their help to protect their countries and the sanctity of Muslims against the aggression or oppression of unbelievers or any aggressor.
Muslims are obliged to support one another and cooperate in righteousness and piety against their enemies.
Yet, if they are still in need of additional help against their enemies or against whosoever – among those belonging to Islam – forms intrigues against them and commits aggression against them, then it is permissible for them to seek the help of whosoever stretches his hand to help and ward off aggression and protect Muslim countries…”
Ref: http://alifta.com, Fataawa Bin Baz, volume 6, The Iraqi invasion is a grave crime
Side Point 1:
Shaykh Salih ibn Abdul Aziz Aal al-Shaykh has said (speech summarised), “…Tawaalli is allying with the kuffar against the Muslims in war to give the kuffar victory over the Muslims. This alliance is based upon complete love for the kuffars religion or ideology (i.e. democracy, secularism ect) this is major kufr which nullifies a persons islam.
Muwalaat is allying with the kuffar against the Muslims in oder to give them victory over the Muslims. Based upon a wordly benefit like money, power, influence ect. This is a major sin but not kufr in any way.
Isti’anah is seeking assistance from the kuffar instead of Muslims or employing them to do something instead of Muslims in certain situations the scholars have ruled this is halaal and entails no sin…” Ref: Islamic Principles For The Muslims Attitudes During Fitnah By Shaykh Salih ibn Abdul Aziz Aal al-Shaykh
Side Point 2:
My Words (Abdul Kareem Ibn Ozzie) – At times allying with the kuffar against Muslims is halaal, at times it is haraam and at times it is major kufr.
Thinking it is always haraam, always halaal or always major kufr is wrong.
Allying with them out of need/necessity against a Muslim force who are or are seeking to harm other Muslims physically is halaal to protect and defend those Muslims from being harmed physically if the Muslims are too weak to defend them Muslims themselves.
Allying with them due to loving the kuffars religion or ideology (democracy ect) is major kufr.
Allying with them due to a wordly benefit is haraam and major sin but not major kufr.
Allying with them due to being forced by the kuffar is halaal as the Muslims in this situation have no choice.
Posted by Abdul Kareem Ibn Ozzie