This is part three of our three-part series on the war in Afghanistan. Part one explained why 2016 could be a very bad year for the country. Part two discussed the emergence of ISIS in Afghanistan.

2016 is shaping up to be a potentially critical year for Afghanistan. ISIS is rising there, the Taliban is gaining ground, the stability of the Afghan government is deteriorating by the day, and national elections are coming in October. The US, China, Pakistan, and the Afghan government are currently holding talks aimed at bringing the Taliban to the table to try negotiate an end to the war.

Of those countries, it's Pakistan that is the most significant. Pakistan has probably the most influence of anyone over whether those talks will succeed in getting the Taliban to agree to sit down and negotiate a peace agreement with the Afghan government. But there's a lot more going on with the peace talks that are perhaps the country's best or only remaining hope.

To understand how this works and why it matters, I spoke to Vanda Felbab-Brown, a senior fellow in the Center for 21st Century Security and Intelligence at the Brookings Institution and an expert on Afghanistan. What follows is a transcript of our conversation, lightly edited for clarity and length.

Jennifer Williams: Could you start by just explaining how Pakistan has been involved in the conflict between the Taliban and Afghanistan historically?

Vanda Felbab-Brown: That goes back to the creation of independent Pakistan, with issues having to do with the Pashtun minority in Pakistan, which is also the majority population of Afghanistan, and irredentist claims by Afghan Pashtun politicians, as well as the Cold War rivalry between the Soviet Union and the United States, who at different times supported either Pakistan or Afghanistan and played the two against each other.

Then you have the Taliban emerging in the 1990s, and Pakistan fully supports the Taliban: They help equip it, they provide intelligence, advisers, and during the Taliban era when they ruled country, Pakistan is one of only three countries that recognize the Taliban regime.

They continued supporting the Taliban throughout the past decade, and US-Pakistan relations became very fraught and complicated. It's never been easy. Pakistanis sometimes use the expression that the United States treats Pakistan like a condom: uses it when they need it then discards it when they are finished with it. It's a fairly common saying in Pakistan, especially in the military. So there is a sense of betrayal on the part of the United States, untrustworthiness, that it's an exploitative relationship on the part of the US toward Pakistan.

"The summer will be very bloody ... even if the Taliban comes to the negotiating table, we are looking at years of negotiations, and certainly no breakthrough before 2017 and likely much longer"

I should also say that Pakistan has long supported many Islamic extremist groups as part of its asymmetric policy toward India, and some of these groups have now mutated, or they slipped Pakistan's full control.

Even with respect to the Afghan Taliban, there is a lot of support from the Pakistani state intelligence services and military to the Afghan Taliban. At the same time, Pakistan has been under enormous US and international pressure to act against them, and so they will take the occasional action against the Afghan Taliban as well. But those actions are mostly seen as halfhearted, incomplete window dressing.

JW: So what role is Pakistan playing today? I know that they just had the four-party talks and that Pakistan has been insisting that these talks take place in Pakistan. Are they trying to speak for the Taliban?

VFB: I'm not sure that it's a fair characterization that they are speaking for the Taliban. Certainly the Afghan government, including in the latest talks, often insinuates or alleges that Pakistan speaks for the Taliban. But they clearly do not.

The relationship between the Taliban and Pakistan is hardly smooth and perfect. Many members of the Afghan Taliban deeply resent the level of Pakistani interference, even as the group has been supported by Pakistan. There is a lot of Afghan Pashtun nationalism also among the Taliban that deeply resents the influence and attempts at control by the Pakistani state.

Part of the key issue in the relationship is that although Pakistan supports the Afghan Taliban, and although it has historically supported other extremist groups, it does not have perfect control. And arguably, its control is diminishing. And so they posture, they do their double game. They want to appear strong, and so they posture that they have much greater control than they have, but at the same time they deny that they have any nefarious role.

In reality, they are playing both sides against the middle, and they often have much less capacity to control and rein in the extremist groups, including the Afghan Taliban, than many assume. The widespread criticism of Pakistan is one of its duplicity and its nefarious activity and its lack of willingness to act against the Afghan Taliban. Those are true, but they are also coupled with limits to their capacity. They are riding a tiger that they cannot control fully.

So they have been hosting these four-way talks that involve them, the US government, the Afghan government, and the Chinese government. The Afghan government is desperate to achieve some sort of negotiated deal with the Taliban. It feels under tremendous pressure, the military is taking a pounding from the Taliban, and the government lacks legitimacy.

The US has similar views on the notion that the way out of the predicament in Afghanistan is a negotiated deal. The Chinese also like the idea. They have their own influence in Pakistan. China would very much like to say that they finally achieved what the US failed to do over the past decade, that they will bring peace to Afghanistan, and that they will do it by enabling the negotiations.

Pakistan is responsive to China. Their relationship with China is much stronger than their relationship with the United States. They often tell the US that China is their old friend, that China is the country that hasn't betrayed them, unlike the United States. China has promised massive economic development in Pakistan at $40 billion. The Pakistanis often say to the US that the Pakistan-China relationship is "greater than the Himalayas and deeper than the ocean." Very flowery.

JW: What's the relationship like between the Afghan government and Pakistan today?

VFB: The crucial man there really is the Pakistani chief of the army staff Raheel Sharif; no relation to [Prime Minister] Nawaz Sharif. I think that there is sort of goodwill and motivation right now, even on the army staff — but that is juxtaposed with, again, the limits of control even the chief has. With almost clockwork regularity you have a round of negotiations in Pakistan or you have a meeting between Raheel Sharif and [Afghan President Ashraf] Ghani, and the next day a bomb goes off in Kabul and people die, or the Indian consulate is attacked.

All those ploys are meant to destroy any beginning of a more positive relationship and have been very effective in subverting the process. The same goes on between Pakistan and India. Meanwhile, Ghani is taking an enormously risky strategy with respect to the negotiations. It's vastly unpopular in Afghanistan, and many, many Afghans hate Pakistan and blame it for all of their troubles.

They use Pakistan as the explanation of everything that ever goes wrong in Afghanistan. And the Pakistanis are responsible for a lot, but there's much, much blame and responsibility that lies on Afghan politicians and Afghan people.

So Ghani's outreach and engagement with Pakistan is extremely unpopular. He's spending an extreme amount of political capital, and does not have support from his partner in the government, Abdullah Abdullah, and the northern Tajik factions that hate Pakistan with great vitriol. So the more Pakistan is unable to deliver things like the Haqqani network, reducing or stopping its attacks in Kabul, the more politically impossible for Ghani the process will be.

JW: So what does that mean in terms of the stability of Afghanistan's unity government?

VFB: The unity government is extremely strained. "Unity" it isn't. The Pakistani negotiation angle is just too big for the strain. It might be strategically important. It might be a very significant element in getting any negotiation going, but it's also extremely politically costly, and the longer it doesn't produce anything, the more politically costly and unsustainable it will be.

In October, there are supposed to be parliamentary elections and district elections in Afghanistan, and, more important, this loya jirga [a national assembly of Afghan elders]. And unless there is some sort of major breakthrough by the summer, a lot of the negotiations and political process with both the Taliban and Pakistan will be put on ice, because it will just be politically impossible in the context of the loya jirga and the elections.

So they really have until the summer to make some sort of breakthrough, and then you will have months of morass and extreme political instability in Afghanistan, but it will also not be conducive in any way to improving either the relationship with Pakistan or the negotiations.

JW: How does Pakistan fit into the rise of ISIS in Afghanistan? What's the relationship there? And how might this affect the peace negotiations?

VFB: The rise of ISIS-Khorasan is one of the most interesting developments. It complicates the negotiations for the Taliban. They oppose the negotiations, and they're a big problem for Mullah Mansour and those who want to negotiate. They enable defections, make them easy, and make them costly.

At the same time, it is interesting because ISIS does not have the same linkages to Pakistan that the Afghan Taliban had, even though ISIS includes many defectors from the Taliban. They quite specifically reject what they call the "yoke" that Pakistan has put on the Afghan Taliban, and they call the Afghan Taliban leadership traitors because of the close relationship with Pakistan.

Moreover, ISIS-Khorasan also has quite a few members of various Pakistani extremist groups like Lashkar-e Taiba and members of TTP [Tehrik-e Taliban Pakistan]. So there is also a lot of resentment and hostility toward Pakistan.

I think the rise of ISIS might make Pakistan be cooperative to some extent, but on the other hand, I think it will also reinforce in the mind of many Pakistan security controllers that it's important to cultivate the Afghan Taliban as friends against the bigger danger of ISIS.

JW: Now that ISIS-Khorasan has directly targeted Pakistan, the consulate in Jalalabad, do you think Pakistan will take action?

VFB: I think they'll take action against ISIS and groups like Tehrik-e Taliban. I don't think it will produce more resolve to go after the Afghan Taliban. That's my view. Others are hoping that they will finally accept the realities and really believe that they have to fight all of the insurgents, all of the terrorists, and that they cannot differentiate among them. I am not persuaded that that will, in fact, happen.

JW: So what does this all mean for the prospects for peace? Are you hopeful at all?

VFB: I think the peace negotiations are important, but I am skeptical that anything will happen quickly.

I think that if by summer the Taliban has been willing to join the negotiating table, that will be an important breakthrough, but nothing will be agreed. The summer will be very bloody, and then there will be the political [wrangling] associated with the loya jirga and the elections.

In my view, even if the Taliban comes to the negotiating table, we are looking at years of negotiations, and certainly no breakthrough before 2017 and likely much longer.

And so the question is whether we, the United States, are prepared to stand by with Afghanistan for that long and whether the Afghans will have the resolve. So it's really important that the military and the police fight as hard as they can, because the weaker they fight, the more they defect, the more intimidated they are, the more brain drain that flows from Afghanistan, the stronger the Taliban is viewed and the more intransigent they will be in the negotiations. Now the negotiations will be very much about the military battlefield as much as they will about what's happening at the table for a long time.