U.S. experts are divided on whether the U.S. and NATO forces should quit as the war in Afghanistan approaches its eighth anniversary and has shown little improvement.

U.S. Congress is growing impatient and so does the American public.

A recent Gallup poll found that half of Americans are opposed to sending additional troops to Afghanistan, down from 65 percent who supported President Barack Obama's order to deploy 17,000 extra troops in February.

'US should call it quits'

Reflecting that sentiment, some experts began to call for a U.S. pullout.

Speaking on Friday at a panel at the Capitol Hill, Malou Innocent, a foreign policy analyst at the Washington-based CATO Institute, made her case for withdrawing U.S. troops from Afghanistan.

The United States, she said, has made a number of incorrect assumptions, such as lumping al-Qaida --an international network of terror cells --in with the Taliban, a tribal organization with no global agenda.

She noted findings by the New York Magazine's Lawrence Wrights that the Taliban was divided over whether to shelter Osama bin Laden prior to the Sept. 11 attacks.

Bin Laden wanted to attack Saudi Arabia, which would have defied a pledge by Taliban leadership to keep the al-Qaida leader in check.

That, she said, shows the Taliban could be wary of sheltering a group that could lead to its own overthrow.

Critics are also increasingly viewing nation building in the mostly rural and tribal nation as a social engineering boondoggle.

Ted Galen Carpenter, vice president for defense and foreign policy studies at CATO Institute, who also spoke at Friday's panel, said Western-style democracy is unlikely to take hold in a deeply divided society such as Afghanistan.

"(The United States) has a nasty tendency to project our values onto other cultures," regardless of whether it is appropriate to do so, he said.

"Afghanistan will never be a Central Asian Alaska or Arizona," he said.

Carpenter expressed caution over U.S. attempts to "win hearts and minds," a strategy aimed at thwarting Taliban recruiting efforts.

"I'm awfully skeptical of winning hearts and minds with an occupying force," he said. "We tried to (do that) in Vietnam and it didn't work well at all."

'More troops needed to defeat Taliban'

Meanwhile, other experts argued that Obama should put more troops on the ground to wipe out the Taliban so it can do no harm to Western interests.

Lisa Curtis, a fellow at the Washington-based Heritage Foundation, said Obama has over the last six months back-peddled on the issue of thwarting Taliban attempts to rule Afghanistan.

In a speech in March, Obama said, "If the Afghan government falls to the Taliban -- or allows al-Qaida to go unchallenged -- that country will again be a base for terrorists who want to kill as many of our people as they possibly can."

But at last week's United Nations General Assembly, the president didn't mention the necessity of preventing the Taliban from destabilizing Afghanistan, Curtis said.

She and other analysts said sending additional troops to Afghanistan would enable the U.S. and NATO to "hold" areas, although they may have to remain in Afghanistan for a decade to keep out the Taliban.

The Taliban and al-Qaida share the same anti-Western goals, Curtis said.

"It would be folly to think a Taliban-controlled Afghanistan would be anything but a deadly international terrorist safe haven," Curtis said.

Curtis contended that U.S. domestic politics are clouding Obama's thinking.

"Obama must shun the temptation to believe that the U.S. can somehow defeat al-Qaida without preventing Afghanistan from being engulfed by the Taliban-led insurgency," she said.

McChrystal's recommendation for additional troops is based in part on the recent American experience in Iraq, where U.S. General David Petraeus' "people-centric" approach to counter-insurgency paid dividends and ultimately discredited al-Qaida and its harsh tactics, Curtis said.

Allowing the Taliban to take over Afghanistan could also have the follow-on effect of emboldening international terrorists in the region, Curtis said.

Stephen Biddle, a fellow at the Council on Foreign Relations and also an advisor to McChrystal, said pulling out of Afghanistan could lead to the Afghan government's replacement by an enemy hostile to the United States.

Biddle said an additional surge of troops -- and a long-term presence -- is needed to protect villagers acting as informants. "The enemy is concealed," he explained.

"And their identity is known primarily to the civilians who live in the area and know, unlike the military operating there, who's who, in spite of the fact that the insurgents aren't wearing uniforms," he noted.

Failure to protect Afghanistan from the Taliban could lead to a destabilizing regional influence and create a base for Taliban fighters to launch attacks against Pakistan and the West, Biddle said.

Much of the current U.S. strategy in Afghanistan rests on a "clear, hold, build" mantra that aims to "clear" areas of Taliban forces and build the economy.

But critics said Taliban fighters are elusive -- vanishing when foreign troops appear and re-emerging when they leave -- which limits U.S. and NATO troops' ability to clear an area.

Such doubts come during an apparent disconnection between military leadership and the White House, analysts said.

In a report leaked to U.S. media, U.S. Commander General Stanley McChrystal outlined a strategy for more U.S. troops.

At the same time, Vice President Joe Biden seemed to suggest just the opposite -- a shift toward smaller units to pursue al-Qaida cells in Pakistan and Afghanistan.