While the nation awaits the administration’s plans for Afghanistan, few expect that decision to make any mention of India. But it should.

When Richard C. Holbrooke was introduced as the U.S. special representative for Afghanistan and Pakistan, India was a glaring gap in his portfolio. However, during the last nine months it has become clear there is no sustainable solution in the region until this gap is filled. Success in the region will largely depend on whether we are able to bring India back into the mix.

India is crucial to any resolution. First, whether real or imagined, Pakistan considers India a serious threat. As the recent debate over the Kerry-Lugar bill suggests, few things agitate Pakistanis more than a perceived threat to their sovereignty. These nuclear neighbors, India and Pakistan, lived through a partition only 60 years ago that cost more than a million lives, they have fought three major wars since, and they continue to maintain thousands of troops on their shared border. As a result, Pakistan’s paranoia over the eastern border they share with India directly impacts its political will and resources to support U.S. efforts on their western border with Afghanistan.

Second, Pakistani sensitivities explain their mixed messages regarding militants. Although recent events indicate Islamabad is changing its tune, many observers believe the Pakistani military, which nurtured these forces in the past, considers these fighters a deterrent against India. Evidence suggests the militants feel the same.

For instance, after the Mumbai bombings, Taliban spokesman Maulvi Omar noted that if India “dared to attack Pakistan” the Taliban would “put aside” fighting the Pakistani army and “defend their frontiers, their boundaries and their country.” Hence, Pakistan may be willing to live with the same insurgents the United States is trying to defeat. Furthermore, Pakistan is unlikely to allow a hostile, or even a neutral, Afghanistan to be stable.

Neutrality equals support for India. Pakistan cannot afford to be surrounded on both sides by potential adversaries. Recent intelligence suggests that India may be exacerbating the situation by using their consulates in Afghanistan to support clandestine activities in Pakistan, particularly the restive Baluchistan province. It is not surprising, then, that Islamabad has failed to fully cut ties with the Taliban, who are not only from Afghanistan’s largest ethnic group, the Pashtun, but who present a means for countering India’s growing influence in Afghanistan. A failure to recognize the Pakistani position only complicates U.S. desire for a strong central Afghan government.

Finally, India is crucial to any resolution because of the continued dispute over Kashmir, called “the most dangerous place in the world” by former President Bill Clinton. India has half a million troops in Kashmir, the largest military deployment in the world, and this territory remains the primary source of militancy and nuclear tension in the region. All major militant groups in Pakistan have some link to the Kashmiri fight. More important, these groups have an extensive network and roots in the region, unlike al Qaeda.

The recent bombings in the Punjab, Pakistan’s most populous region and home to many Kashmiri militant groups, suggest growing ties between local militants and global jihadists; a potent mix of indigenous networks and al Qaeda expertise. The more Pakistan has to focus on this militancy, the less it can support U.S. objectives on the frontiers.

So, what must be done? The obvious first step is to include India in Mr. Holbrooke’s portfolio. This would send a strong signal that we are interested in a comprehensive regional solution. Second, we need multilateral efforts to begin resolving the issue of Kashmir. Aside from tackling the core security challenge in the region, this would give political cover to a fledgling Pakistani democracy.

Finally, we need to find ways to give a greater stake in Afghanistan’s stability to the Pashtuns, who retain strong tribal ties across the border in Pakistan. This will help allay Pakistan’s concerns about its ability to exert influence in Afghanistan over the long term and, thus, secure a more sustained commitment from them against those militants who pose the greatest threat to us.

Naturally, these steps must also be accompanied by measures to reassure our Indian allies, who have borne the brunt of militancy on numerous occasions. Regardless of what concrete steps we take in the region, our approach must consider the larger strategic context. In doing so, one thing must be clear: India can no longer be absent from the discussion.

Adnan A. Zulfiqar is a fellow at the Truman National Security Project and a former Senate staff member.  This essay was previously published as “India must be included: Comprehensive regional solution is the ticket” in the Washington Times.