Can a Muslim country levy war on a Muslim country?

A Muslim country cannot levy war on another Muslim country; brother cannot kill brother. It is binding both for individuals and for nations. Messenger of Allah (pbuh), not only forbid killing other Muslims he also forbid pointing a weapon on him and stated, Anyone of you cannot point a weapon to your Muslim brother.

Disagreements must be raveled out by talking. If the disagreement cannot be solved by negotiations, arbitration commission should be elected. Therefore, opposing parties should assent to the decision of the arbitrator. If one side withdraws arbitrators consent, becomes illegitimate in its claim and it is held responsible to start a war. The most important issue that takes attention here is arbitrators being neutral and being on the side of the rightful.