A leading moderate Senate Democrat is calling for clear benchmarks to measure progress in Afghanistan as the Obama administration reviews U.S. strategy there.

“It is our responsibility to ensure that the American people are given a clear objective for the mission in Afghanistan, one which contemplates defense, diplomacy and development,” Sen. Ben Nelson of Nebraska, a member of the Armed Services Committee, wrote in a March 4 letter to Secretary of State Hillary Rodham Clinton and Defense Secretary Robert M. Gates .

Nelson said he may try to add benchmarks to the upcoming war supplemental bill this spring or the fiscal 2010 defense authorization bill later this year.

There has been growing concern in recent months about the direction of U.S. policy toward Afghanistan amid a resurgence of the Taliban, the Islamist militia which ran the country before the 2001 U.S. invasion. Afghanistan’s new central government has been unable to secure the country.

Last month, President Obama ordered the deployment of 17,000 additional troops to Afghanistan, to augment the 38,000 already there.

Meanwhile, an Afghanistan strategy review is under way, with results expected in the coming weeks.

Nelson was among the Senate moderates who pushed for the inclusion of 18 benchmarks for Iraq in the fiscal 2007 supplemental war funding bill. Those benchmarks called for concrete progress on a variety of issues, including the integrity of Iraqi security forces, the allocation of reconstruction funds, and the fair treatment of minority political parties.