President Obama’s pick to succeed Gen. Martin Dempsey as the administration’s top military advisor will ratchet up pressure on the White House to delay the withdrawal of US troops from Afghanistan.

Gen. Joseph Dunford, Obama’s nominee to be next Joint Chiefs of Staff chair, said in his confirmation hearing that, if approved by the Senate, he would advise the president to set a benchmark for an Afghan pull-out “based on the conditions on the ground.”

“My experience has been that sometimes the assumptions you make don’t maintain, particularly with regard to time, and that’s certainly the case in Afghanistan,” he told Senate Armed Forces committee chair, John McCain (R-Ariz.).

Dunford repeated the “conditions on the ground” in Afghanistan line to Sen. Jim Inhofe (R-Okla.), and vowed to “certainly go over there and check those, if confirmed.”

And in response to a series of questions from Sen. Lindsey Graham (R-S.C.), Dunford predicted dire consequences if the 10,000 troop-strong contingency is pared back significantly at the end of 2016, as President Obama is currently planning.

“My assessment is we’d have a significant degradation of our counterterrorism mission in Afghanistan,” Dunford commented.

“Would we lose our eyes and ears along the Afghan-Pakistan border that we enjoy today?” Graham asked.

“We would, Senator,” Dunford responded. “There’s no question it would create risk,” he said, in reply to a follow-up.

There appears to be little resistance to Dunford’s nomination. McCain said he supported the pick and told the general he was “confident you will serve with distinction.” Graham called Obama’s selection an “outstanding choice.”

The Afghan troop withdrawal issue came to the fore earlier this week, when former CIA Director and leader of forces in both Iraq and Afghanistan, Gen. David Petraeus, wrote an op-ed criticizing President Obama for moving forward with his timetable.

“The right approach is for Obama to protect our investment in Afghanistan and to hand off to his successor military forces and tools that will still be critically needed in 2017 and beyond,” he co-wrote in the Washington Post, alongside Brookings Institute senior fellow Michael O’Hanlon.

Dempsey, too, has publicly expressed skepticism about the wisdom of a withdrawal. In testimony before the Senate Armed Services Committee earlier this year, he said Afghanistan was an “anchor” in the US government’s conflict against Islamist extremists.

Although President Obama made a point of demonstratively calling the downsizing of US forces at the end of last year “the end of the combat mission in Afghanistan,” there was reportedly an uptick in American military activity there over the winter–missions that took place “in the shadows,” as one former Afghan official told The New York Times in February.