Niger is a sovereign state, why should ECOWAS invade it?

This is what Atiku Abubakar, a former Nigerian Vice President wrote regarding the ECOWAS interest to militarize efforts to reinstate democracy in the Niger Republic:

“The military intervention in the Republic of Niger has created tension across the West Africa sub-region, and it is a development that has caused international attention to that neighboring country of ours. The putsch is even more worrisome because the number of states that have witnessed military intervention in the last three years in the subregion is increasing. Of course, the world expects Nigeria to take up leadership in ensuring that the crisis of political leadership in the Republic of Niger is not just curtailed but also ensuring the restoration of democratic governance in that country. While the expectations that fall on Nigeria as the sub-regional leader are not a quick fix, it must be expressed that the role taken so far by the Economic Community of West African States has been commendable. As the ECOWAS continues to work towards reinstating democracy in the Republic of Niger, it must be reinforced that the regional body should not travel the road of military hostilities that may exacerbate the status quo. The crisis in the Republic of Niger requires diplomatic engagements, and that must mean that the channels for dialogue should be well sustained. While the world expects Nigeria to take a leading role in this process of peaceful conflict resolution, it must be clear to the military insurrectionists in the Republic of Niger that the world cannot afford to wait for too long before this crisis is resolved reasonably. This is undoubtedly a challenging time for the West African region. However, any actions taken towards the prompt resolution of the crisis in the Republic of Niger must prioritize democracy as the ultimate victor.”