I've seen occasional recent references  comparing  Pakistan to Cambodia during the Vietnam War.  If the Bush administration, or Barack Obama, thinks the two are comparable it is making the biggest miscalculation since the U.S.  made the mistake of getting too close to China in the Korean War.   Obama wants to expand the current Bush attacks on border areas to include an attack on Osama bin Laden where ever he might be in Pakistan.

U.N. forces had routed the North Korea Army and appeared to on the verge of winning when China became concerned that the Americans might decide to go ahead and conquer China as well because China had been supplying the North Koreans.  China responded by sending in its army.  President Harry Truman decided that it was best not to antagonize the Chinese any more than necessary and prohibited  bombing supply bases in China.

Enemies using sanctuaries  isn't a new situation for the U.S.  Andrew Jackson faced such a situation  along the border of what was then Spanish owned Florida during the administration of President James Monroe.  Jackson took care of the problem by in effect declaring war on Spain with nothing more than an ambiguous letter from President Monroe. Jackson invaded Florida without any authorization from Congress and captured the Spanish governor at a poorly defended fort at Pensacola.  Spain after a protest decided Florida wasn't worth the trouble and ceded it to the U.S.

 During the Vietnam War communist forces started using areas  of Cambodia along the Vietnam border as sanctuaries for supply depots and troop bases.  Cambodia with a population of only 7 million and no military force to speak of couldn't force the Vietnamese out and was afraid that acknowledging their presence would draw the country into the war.  North Vietnam denied having any forces in Cambodia. 

The U.S. occasionally bombed these forces and sent in commando type forces, but denied doing either.  The U.S. didn't want to formally enter the country because it didn't want to  risk forcing Cambodia to ask for assistance from someone like China or the U.S.S.R.  Cambodia also ignored the actions of  the U.S. claiming it wasn't aware of the presense of foreign troops or any bombing. 

In early 1970 Prince Norodom Sihanouk's efforts to keep the country out of the conflict failed and he was overthrown in a coup by pro-U.S. officials.   The new government  invited the U.S. in to eliminate the communist bases.  Subsequently the country endured a civil war that resulted in over a million deaths.

Pakistan with an estimated 2006 population of 165 million is the 6th most populous nation in the world with a population equal to the population of Iraq plus the population of  Russia.  It has the world's 7th largest military force, including nuclear weapons and missiles to deliver them.   Pakistan's population is approximately equal to the combined populations of World War II Germany and Japan. 

Militants are a potential threat to overthrow or even take over the government.  They would welcome an incident  they could use to attract support for  a  Jihad type war. 

Al Qaeda may be using Pakistan as a sanctuary as part of a  strategy to create an incident to draw Pakistan into their Jihad.  Osama bin Laden  might welcome  being killed if he could  achieve martyr status  and induce Pakistan to declare war or to start supplying his forces with conventional or nuclear weapons. 

Pakistan has already had a problem with a government scientist helping other countries develop nuclear weapons without government approval.  Other government officials might respond to a U.S. incident by allowing militants to "steal" nuclear weapons.  If those militants could also "steal" a missile that could be fired from  a ship, they might be able to destroy a U.S. city.

The United States have enough to handle without having to take on a major military power like Pakistan.  Al Qaeda sanctuaries in Pakistan do increase the hazards of those serving in Afghanistan just like the Cambodian sanctuaries increased the  threat to those of us who served in Vietnam.  The rockets and mortars fired in my direction may have been stockpiled in Cambodia before being provided for attacks.  The Viet Cong and North Vietnamese forces where I was took their R & R in Cambodia.

However, the potential threat of a  much wider war makes the risk of attacking sanctuaries, or attempting to attack Osama bin Laden as Barack Obama wants to do,  too great to take the chance.  Pakistan isn't a weak nation like Cambodia or early 19th Century Spain. Pakistan has a stronger military force than China had during the Korean War.  Little Iraq ignored an ultimatum. Why would any intelligent person think Pakistan would take orders from the U.S.?