Can the United States send armed forces into another state to deal with a national security threat from a militant group when the host state is “unwilling or unable” to contain the threat? That question has been a focus of debates among international legal experts including Daniel Bethlehem, Ashley Deeks, Kevin Jon Heller, Christian Tams (plus many others in the American Journal of Int’l Law in April 2013 and July 2013).

Last week — with far less international attention than I would have anticipated — Iran appeared to invoke the “unwilling or unable” test threatening to use force in Pakistan and Afghanistan. The case is perhaps limited to its specific facts, which involves the abduction of Iranian border guards who are being held inside Pakistan (reportedly by militant group Jaish al-Adl). That said, some of the remarks by Iranian officials also suggest the assertion of a broader right to use force with respect to the threat of militant groups operating out of Afghanistan and Pakistan, not just the specific case of these abductions.

Here are some of the key statements coming out Iran:

“If Pakistan doesn’t take the needed steps to fight against the terrorist groups, we will send our forces into Pakistani soil. We will not wait for this country.”
— Iranian Interior Minister Abdolreza Rahmani-Fazli (quoted in Reuters and Mehr news agency)

“Tehran’s interior minister has warned Pakistan that Iranian forces may enter Pakistani and Afghan territory to released[sic] border guards seized by a rebel group.

He said Iran had asked Pakistan to treat the case ‘strongly and seriously’ or allow Iran to secure the remote region ‘deep on[sic] Afghanistan and Pakistan soil.’
‘Otherwise we do consider it our own right to intervene and create a new security sphere for our safety,’ he said.”
— Associated Press


In some minds, this case provides evidence of the acceptance of the “unwilling or unable” test in international law and practice. For others, it will count as evidence that norms being set by the US have dangerous and unanticipated consequences–by lowering the threshold for the use of force. And for others still, it will count as evidence that the unwilling or unable test may be effective in encouraging a host state to control armed groups within its borders.

Late last week a Joint Iran-Pakistan Border Commission formed a committee to address the border issues involving militants, and Pakistan and Iran have since begun conducting joint patrols to find and rescue the border guards.