It is quite understandable why Pakistan would like to join the enquiry into the straying of an Indian BrahMos missile into Pakistan. However, the kind of deliberation and measured response with which met the intrusion should continue, and the diplomatic channels used so far should be allowed to continue to progress normally. Pakistan should realize that India will display its traditional paranoia about letting Pakistan anywhere near its precious missile, or even any enquiry establishing what went wrong, allowing a missile fired in Haryana landing in Pakistan.
The main danger of such an accident is that it could spark off an escalatory ladder that might lead one side to launch a nuclear weapon. Vigilance makes this necessary on both sides.
Pakistan had no means of knowing that the missile was not carrying a nuclear payload until it landed near Mian Channu. It is also fortunate that it landed in an empty area, and did not land in a built-up area. It is also fortunate that its path did not cross that of any civilian airliner. These pieces of good fortune cannot be ascribed to any wisdom or prudence, but were the result of mere chance. Such incidents must be avoided, because the other side might respond aggressively. A joint investigation would also lead to a means of developing procedures for the two countries to follow in the event of such accidents.
One reason Pakistan has for joining the investigation can be accomplished without doing so, and that is a thorough examination of all relevant procedures and protocols. Pakistan should remain aware that the present Indian government is seeking a casus belli, and thus it should make sure that there are no inadvertencies or mistakes that would provide any excuse.
As it is, the ‘mistake’ provided a check of the PAF’s and the Pakistan Army’s ability to respond. It would not be beyond India to fire off an expensive blank as a test. Presumably the swift and professional response of both will have shown India that any aggression will be met appropriately.