ASHRAF GHANI AHMADZAI

Age: 65

Education: Bachelor's degree, American University, Beirut; master's, Ph.D. in anthropology, Columbia University

Career: Faculty member, University of California, Berkeley, 1983, John Hopkins University, 1983-1991; lead anthropologist, World Bank, 1991-2001; special adviser to United Nations special envoy to Afghanistan, 2001; chief adviser to Afghan President Hamid Karzai, minister of finance, 2002-2004; chancellor, Kabul University, 2004-2008; candidate for president of Afghanistan, 2009; founder, Institute for State Effectiveness. Sworn in Monday as president of Afghanistan.

Republicans have said the failure of the Obama administration to reach such an agreement in 2011 with Iraq, and the total withdrawal of U.S. troops that followed, left the country open to the Islamic State insurgency that now threatens it and is drawing the U.S. military back into the region.

As Afghanistan’s previous president, Hamid Karzai left the political stage, Ahmadzai was locked into an uneasy partnership with his defeated rival, Abdullah Abdullah, who became the country’s first chief executive. With a hug for the cameras, both sides appeared determined to reach across factions and avoid the sectarian divisions that afflicted Iraq, helping to fuel the insurgency.

The new Afghan government is expected today to sign the security agreement, which will provide a legal framework for the United States to keep about 9,800 troops in the country to train, advise and assist Afghan national security forces after the current international combat mission ends Dec. 31. The number would fall to about 1,000 after 2016. Karzai had refused to approve the deal.

The Afghan government also is expected to sign an agreement this week with NATO that would allow 4,000 to 5,000 additional international troops — mostly from Britain, Germany, Italy and Turkey — to stay in Afghanistan in a noncombat role after the end of this year.

Without a post-2014 residual force, U.S. military officials say, there is a risk that the Afghan security force will deteriorate, units will run out of fuel, pay systems will fail and there will e a reduction in the overall readiness of the Afghan police and army. They say al-Qaida is in “survival mode” in Afghanistan, but that if all international forces left this year, the terrorist network would see it as a victory, regroup and again use the region to plan and conduct operations against the West.

But there are serious questions about the ability of the Afghan security forces to take on the militants, even with a residual U.S. force — down from a high of more than 130,000 U.S. and NATO troops in Afghanistan several years ago.

“Afghanistan doesn’t have the full military necessary to defend the country,” said Mohammad Doud Kalakani, a member of the Afghan parliament. “No air force, no tanks, limited artillery.”

U.S. House Armed Services Committee Chairman Rep. Howard “Buck” McKeon, R-Calif., said Monday that he hoped President Barack Obama would view the signing of the security agreement as a “roadmap for a robust continued engagement, and not a path to premature withdrawal.”

McKeon also wants the administration to rethink its plans to draw down U.S. forces. “We are witnessing now in Iraq what happens when the U.S. falters on that commitment and adopts a posture inconsistent with our security interests,” McKeon said.

U.S.-Afghan relations will likely improve under Ghani Ahmadzai. Karzai, the country’s only leader since the 2001 U.S.-led invasion, frequently criticized the U.S. government and irritated American leaders with his mercurial behavior; Karzai was criticized in turn for his inability or unwillingness to tackle corruption in his own government.

On Monday, however, Karzai wore a wide smile as he greeted his presidential guards upon entering the palace, where he presided over the first peaceful transfer of power in the nation’s history. It was made possible by a constitution that he helped draft and that prohibited him from serving a third five-year term.

Ghani Ahmadzai’s first act in office was to swear in Abdullah as chief executive, a role that U.S. Secretary of State John Kerry helped create to give voice to both Afghanistan’s northern and southern flanks of power.

“Afghans have taken a moment of challenge and turned it into a moment of real opportunity,” Kerry said Monday in a statement congratulating both men.

The deal settled months of political tensions that threatened to push the fragile country into civil war. But it remains to be seen how well the two Afghan leaders will work together, and whether the agreement will last. They still must agree on Cabinet appointments.