Soon after the horrific attacks in Mumbai, India, I spoke with Sen. Hillary Clinton, President-elect Barack Obama's choice for secretary of state, about the challenges we face in South Asia. As we discussed the nations in and around that region that demand our attention — India, Pakistan, Afghanistan, China, Iran — Clinton made it clear she understands that we can't simply take a myopic, country-by-country, issue-by-issue approach to our foreign policy, or our national security. We have to look at the region as a whole, and understand its complexities if we are to head off threats and devise sustainable solutions. As Clinton put it, "We have to be able to walk and chew gum at the same time."

To me, no place better represents the region's complexities than Kashmir. This long-disputed territory has been claimed by India and Pakistan with parts controlled by both countries. On my visit to the Pakistani side of the Line of Control earlier this year, the tranquil mountain views gave no hint of the simmering conflict that has resulted in repeated clashes since the 1947 partition. This relative peace reflects, in part, the fact that relations between the countries have improved, and military activity has decreased. At the same time, however, terrorist groups previously focused almost entirely on Kashmir have metastasized, even supporting attacks in Afghanistan.

The attacks in Mumbai have understandably heightened tensions between Pakistan and India. Last week, the director of national intelligence stated that he believed that the attacks were perpetrated by the same group responsible for a 2006 attack in Mumbai and a 2001 attack on the Indian parliament, strikes that the Indians have tied to Lashkar-e-Taiba, a Pakistan-based terrorist group that has focused on the conflict in Kashmir. A full investigation, with cooperation from all parties, is essential. Regardless of what the investigation reveals, however, we must work to head off a return to conflict between Pakistan and India.

Unfortunately, simply preventing Pakistan and India from going to war is not enough. We must also confront the threat from al-Qaida's safe haven in Pakistan, while addressing the historic tensions between the two countries, including over Kashmir. When I traveled to Pakistan and India in May, I asked senior government officials direct questions about the status of their relations. In both countries, I was told that the major threat is now on Pakistan's western border and that the two countries were committed to working together to address regional security issues.

I also asked members of the newly elected civilian government in Pakistan how they were working to dismantle the terrorist groups previously focused on Kashmir that had begun supporting attacks in Afghanistan. I was assured they were committed to addressing this problem. I came away from these discussions cautiously optimistic that government officials of both countries were seeking improved relations — improvements that risk disintegrating in the coming weeks — but unconvinced that the threats spawned by decades of tension had been eradicated.

Without question, we must maintain our focus on al-Qaida in Pakistan's FATA region and ensure Afghanistan does not once again become a base for attacks on the United States. And we must confront the resurgent Taliban and other extremist groups that threaten stability in Pakistan and the region and provide safe haven for al-Qaeda.

But we must do so while pressing for better diplomatic relations between Pakistan and India, which must include resolution of the dispute over Kashmir. The attacks in Mumbai remind us that, as we work to bring the perpetrators to justice, we have no choice but to walk and chew gum at the same time. The consequences of not doing so are far too serious to ignore.

Sen. Russ Feingold (D-Wis.) is a member of the Senate Foreign Relations Committee.