EN ROUTE TO AFGHANISTAN – I’m in a C-17 transport plane with the chairman of the joint chiefs, Gen. Martin Dempsey, to a change-of-command ceremony in Kabul, at which Gen. “Fighting Joe” Dunford will take over responsibility for the toughest, most thankless job in the military – overseeing the supposed “end” of our Afghan war.

Dempsey, who travels in a shiny pod within the C-17, complete with working and sleeping quarters and secure communications equipment, is genial and thoughtful, and wears a blue baseball cap with the number 18 (he is the 18th joint chiefs chairman). He stressed the symbolism of the command transfer to reporters with him: Dunford will be final commander of international forces in Afghanistan, tasked with winding down America’s longest war.

The glide path is set for the drawdown. Yet there is a real prospect the country could revert to chaos, and re-emerge as a jihadi haven, if the U.S. exit is badly managed. So Dunford takes over when some of the war’s toughest challenges lie ahead.

“The greatest challenge will come as he covers the period between now and December 2014,” Dempsey said during a stopover in Germany. Dunford will have to continue the fight against al-Qaida and its allies even as he directs the withdrawal of most of the remaining U.S. troops with staggering amounts of equipment. He must also oversee the transition, by next summer, to full security control by Afghan forces (ready or not).

Moreover, the four-star Marine general will be dealing with a conflict in which the American public and Congress have lost interest. (In eight hours of confirmation hearings for Chuck Hagel as secretary of defense, there were about 37 mentions of Afghanistan and more than 130 of Israel.)

More daunting, Dunford will be pursuing a White House strategy into which he had no input, and whose details remain murky. The speed of the drawdown and how many troops will remain after 2014 is still being debated, with the White House apparently eager to speed the withdrawal and the military reportedly reluctant to rush things.

Dempsey, however, would not define the optimal speed of the drawdown or the appropriate size of a post-2014 force. “Once we have settled the mission, we can provide options,” he said, and “the military at this point is comfortable that the number will match the mission.”

However, the post-2014 mission is still unclear.

It’s been defined in broad terms: training and assisting Afghan forces and continuing the fight against global terrorism. But, depending on the details, that could involve as few as 2,500 or as many as 20,000 troops; it could hew to a narrow counterterror mission or a broader effort to upgrade Afghan forces and boost morale.

Signals from the White House are contradictory. Recently, a senior administration official said a “zero option” was being considered for after 2014.

“No one has ever mentioned zero to me and I would never recommend zero,” Dempsey said. So why did the White House raise that prospect, and start rumors in Kabul?

Floating the zero option seems even stranger because the performance of Afghan security forces will depend as much on Afghan perceptions of our intent as it will on numbers. If Afghan forces believe the United States is heading headlong for the exits, they may crumble. If Afghanistan’s neighbors – Pakistan, Iran, India and Russia – conclude the administration is mainly focused on leaving, they will line up proxies for the next Afghan civil war.

“What really hangs in the balance is the confidence level of Afghan forces,” says Dempsey, along with the Afghan public’s confidence in them. So how do we convince Afghans we won’t abandon them after 2014?

One way, says Dempsey, is to conclude a bilateral security agreement with Kabul that will enshrine cooperation after 2014. “We want that in place so in 2014 we will know where we are going.”

During his confirmation hearings in November, Dunford said such an agreement would not only show “that we are committed to the long term,” but would also encourage coalition partners to commit to similar arrangements with Kabul. That, in turn, would influence Pakistan, which still lets the Taliban operate out of its territory.

“I think Pakistan hedges its bets based on what they believe our long-term commitment to the region would be,” Dunford told the Senate Armed Services Committee. “And their calculus will be changed as a result of their knowing that we are not only going to be there through December of 2014, but we’ll be there beyond 2014.”

Dempsey believes Pakistan is already more certain Washington won’t abandon Kabul. “Of late, I’ve seen a degree of cooperation on the part of our Pakistani military counterparts that is quite encouraging. I think they finally believe we are not going to shut out the lights and leave.”

Yet negotiations on the bilateral accord have dragged on, although they are supposed to be completed no later than May. Given the administration’s failure to reach a similar security accord with Iraq, one has to wonder if the White House has the will to conclude this one.

Dempsey believes the odds are better for reaching an accord with the Afghans because the process started earlier and the Afghan government has more reason to want a deal than the Iraqis did.

But before an accord can be reached, the White House must decide on its post-2014 strategy.

As we descend into Bagram air base outside Kabul, I can’t help thinking: The sooner that strategy becomes clear, the better “Fighting Joe” Dunford’s prospects will be.