The public believes that the Afghan war is not worth fighting by a 2-to-1 margin — a new low — according to a poll released Tuesday. 

An ABC News/Washington Post poll shows that only 31 percent say the Afghanistan war has been worth fighting, the lowest level of support since the survey started asking the question in 2007. Sixty-four percent say it is not worth fighting, with 49 percent saying they feel that way strongly.

The numbers illustrate the difficulty U.S. leaders face at home as they carry out the war effort in Afghanistan, which has stretched into its 10th year.

The result also comes on the same day the top allied commander in Afghanistan, Gen. David Petraeus, is set to testify before the Senate Armed Services Committee.

A growing group of lawmakers on Capitol Hill are becoming restless with the war effort and are pressing the Obama administration to set a firm timeline for withdrawal. Currently, the U.S. plans to start withdrawing troops in July 2011 and complete the process by 2014, if conditions permit.

Sen. Kirsten Gillibrand (D-N.Y.), according to the Huffington Post, has become the latest lawmaker to support a plan to press the administration to lay out a final deadline for withdrawal.

The plan would endorse July 1 as a start date for withdrawal and would require that President Obama submit a plan to Congress by July 31 for "the phased redeployment of U.S. combat forces, including a completion day," according to the Huffington Post.