The Malian government in January requested military support from its former colonial power France to help thwart the southern advance of Tuareg rebels and al-Qaida militants.
Bamako lost control over northern sections of the country after a coup in early 2012.
Sebastian Elischer, an African researcher at the German Institute of Global and Area Studies, writes in Foreign Affairs that Tuareg rebels in Niger, to Mali's east, are disenfranchised despite a 2009 peace deal.
He says members of the Tuareg group in Mali fled across the border as French and Malian forces pushed north.
"Given Niger's weak government structures, they ... pose a serious security threat to the country as a whole," he writes.
With the international community pressing for a comprehensive political solution in Mali, Elischer warns that failed efforts at democratization make Niger ripe for unrest.
"Niger presents an appealingly easy target," he warns.
Last month, the U.S. State Department warned U.S. citizens to exercise extreme caution if traveling to Niger because of a threat from spillover from Mali.