Kathmandu, May 6 -- India and Pakistan are twins separated at birth. Tensions between them have been at a hair trigger ever since independence and has erupted into full scale conflict at least four times in the past 80 years.

The 22 April terrorist attack in Kashmir that killed 26 Indian tourists, including a Nepali, threatens to escalate tension between the two nuclear-armed nations. India has squarely blamed Pakistan for the attacks, and Prime Minister Narendra Modi has given his military "operational freedom" to respond. Pakistan has said it has credible intelligence of an Indian military strike and its officials have promised a "full spectrum" response - a code for a nuclear retaliation.

For Nepal, the killing of its national in the...