The Obama administration needs to link its counterinsurgency strategy in Afghanistan with efforts to improve governance there to be successful in defeating the Taliban, a former Afghan finance minister said on Wednesday.

Ashraf Ghani, a contender in August presidential elections, credited President Barack Obama with taking steps to create a "second chance" to build a stable Afghanistan after lost years since the U.S. invasion in 2001.

"To commit more forces in this time is an act of both courage and statesmanship," the former World Bank and U.N. official said in remarks at the Atlantic Council think tank in Washington.

In a new strategy for Afghanistan unveiled last month, Obama said he would send in 17,000 more troops and make stabilization of Afghanistan and the war on Islamist militants there a top foreign policy priority.

Ghani, author of a new Atlantic Council report on Afghanistan, said, however, that "forces in themselves are not the answer. It is the strategy that is going to use them that is the issue."

He said the troop increase needed to be wed to a counterinsurgency strategy that supported renewed efforts in four key areas to build up the governing capacity of the Afghan state.

"The game changer is to produce a legitimate election that the next government of Afghanistan can have a mandate," said Ghani, who is seen as an outside contender in the August 20 presidential vote.