Martha Coakley has given us some good news.

“I am not sure there is a way to succeed.  If the goal was and the vision in Afghanistan was to go in because we believe the Taliban was giving harbor to terrorists, we supported that, I supported that goal. They are gone, they are not there anymore, they are in apparently Yemen and Pakistan.  Let’s focus our efforts on where Al Qaeda is.”

Maybe someone should tell the U.S. Marines who would like even more troops to stop the flow of terrorists into Afghanistan.

KHAN NESHIN, Afghanistan — Only a few hundred American troops are policing the southern border of one of Afghanistan’s major smuggling areas, leaving open a vast expanse of desert that the Taliban use to shuttle in weapons and fighters from Pakistan.

This dusty hamlet 75 miles (120 kilometers) north of the border in Helmand province was the Taliban’s key transit point from Pakistan before the Marines arrived in July. Since then, the Marines have set up a series of patrol bases east and west of Khan Neshin to disrupt the Taliban’s supply lines.

But the battalion deployed at only about 50 percent of its authorized strength, and one of its three companies is posted in central Helmand. That leaves several hundred Marines to cover roughly 6,000 square miles (15,000 square kilometers) — an area larger than Connecticut.

As a result, the Marines may have trouble curbing Taliban supply lines as thousands of fresh troops pour into the province as part of President Barack Obama’s surge.

“I would like to push closer to the border, but I can only go as far as I can support,” said Lt. Col. Michael Martin, commanding officer of 4th Marine Division, 4th Light Armored Reconnaissance Battalion.

“Like Napoleon, you don’t want to overextend your capabilities, or you will get your butt handed to you,” said Martin, whose troops are spread out among a handful of patrol bases along the Helmand River, marking the coalition’s most southern presence in the province.

Some 8,500 additional Marines are slated to arrive in Helmand by mid-2010 as part of the 30,000-troop buildup. But any decision to send more Marines south to patrol the largely uninhabited border area would leave fewer troops for the major population centers farther north.

Many Taliban fighters fled to Pakistan following the U.S.-led invasion of Afghanistan in 2001 and found sanctuary in the mountainous belt that runs between the two countries. Obama has pressed Pakistan to target the militants, but many analysts believe the government has resisted because the Taliban could serve as useful proxies if the coalition effort in Afghanistan fails.

That leaves the Marines with the difficult task of disrupting the flow of Taliban fighters into Afghanistan largely without Pakistani help.

“We are trying to make it as difficult as possible for the Taliban to stay connected to their sanctuary in Pakistan,” said Capt. Timothy Newkirk, executive officer of 4th LAR’s Bravo Company, which is based in a 200-year-old mud fort in the town of Khan Neshin.

They (the Afghan Taliban and the Pakistan Taliban, both of whom harbor AQ and other transnational insurgents) are sharing resources, just as they said they would.