The idea that all means, including war crimes, are warranted in defending one's territory is one that I cannot accept.
War crimes are bad, but using ATP land mines is not a war crime by itself.
For example ATP land mines with reliable self-destruction used properly are OK (yes, some failure rate will exist - in case of war you rarely have 100% sunshine and rainbows solutions).
While dropping randomly land mines over city to target civilians is bad, evil, war crime and terrorism.