As laid out in Part (1) of the Principles for Military Intervention Synopsis or paragraph 4.19 of R2P, two broad sets of circumstances satisfies the "Just Cause" or "Threshold Criteria":
a. Large scale loss of life, actual or apprehended, with genocidal intent or not, which is the product either of deliberate state action, or state neglect or inability to act, or a failed state situation; or
b. Large scale "ethnic cleansing," actual or apprehended, whether carried out by killing, forced expulsion, acts of terror or rape.
Part (2)A of the Principles for Military Intervention Synopsis of R2P says:
The primary purpose of the intervention, whatever other motives intervening states may have, must be to halt or avert human suffering. Right intention is better assured with multilateral operations, clearly supported by regional opinion and the victims concerned.
Part (2)B of the Principles for Military Intervention Synopsis of R2P says:
Military intervention can only be justified when every non-military option for the
prevention or peaceful resolution of the crisis has been explored with reasonable
grounds for believing lesser measures would not have succeeded.
Part (2)C of the Principles for Military Intervention Synopsis of R2P says:
The scale, duration and intensity of the planned military intervention should be the minimum necessary to secure the defined human protection objective.
Part (2)D of the Principles for Military Intervention Synopsis of R2P says:
There must be a reasonable chance of success in halting or averting the suffering
which has justified the intervention, with the consequences of action not likely to
be worse than the consequences of inaction.
As discussed in Part (3) of the Principles for Military Intervention Synopsis or Chapter 6 of R2P, there is no better or more appropriate body than the United Nations Security Council to authorize military intervention for human protection purposes. R2P argues that the international community should make the Security Council work better than finding alternate sources of authority.