Facing the "undeniable" threat of another Mumbai-type attack by Pakistan-based terror groups which may act under al-Qaeda's direction, India is most likely to retaliate militarily in such a scenario, according to a prominent US think tank.
"The threat of another Mumbai-type attack is undeniable; numerous Pakistan-based groups remain motivated and able to strike Indian targets," said Daniel Markey of the prestigious Council on Foreign Relations (CFR) in his latest paper 'Terrorism and Indo-Pakistani Escalation.'
Many of these Pakistan-based terror groups have incentives to act as spoilers, whether to disrupt efforts to improve Indo-Pak ties or to distract Islamabad from counter-terror crackdown at home, said Markey, a known South Asia expert.
"Thus the immediate risk of terrorism may actually increase if New Delhi and Islamabad make progress on resolving their differences or if Pakistan-based terrorists are effectively backed into a corner," he said in his 11-page contingency planning memorandum of the CFR.
While traditionally Pakistan-based Lashkar-e-Taiba and Jaish-e-Mohammed are the two terror groups that have proven themselves the most capable and motivated to carry out attacks in India, this time al-Qaeda could don the mantle, he said.
"Al-Qaeda has historically focussed its efforts outside India, but if the group's leadership feels threatened in the Pakistan/Afghanistan border areas, it might direct and assist regional proxies to attack India as a way to ignite a distracting Indo-Pakistani confrontation."
Other regional terrorist groups, including those based in India, are improving their capacity to inflict mass-casualty violence, but because these outfits lack clear-cut connections to Pakistan-based organisations, their attacks are far less likely to spark another crisis between India and Pakistan, Markey said.
He said the more clearly a terrorist attack can be identified as having originated in Pakistan, the more likely India is to retaliate militarily.
He said groups that India perceives to have closer links with Pakistan's military and intelligence establishment -- especially LeT -- are more likely to "inspire retaliation against official Pakistani state targets" than those that are perceived as more autonomous, such as al-Qaeda.
The perception in India that Islamabad has responded inadequately to the Mumbai attacks -- trials of accused plotters are moving slowly and LeT ideologue Hafiz Muhammad Saeed is not in custody -- strengthens Indian advocates for unilateral military retaliation, Markey said.
Should multiple attacks occur in quick succession, the cumulative effect would further diminish India's inclination for restraint, he said.
"Prime Minister Manmohan Singh has been a strong voice against Indian military retaliation, but his voice could be silenced by a future attack or otherwise drowned out by domestic political pressures," Markey said.