Obama IS bombing Pakistan, idiot. I realize you are easily blinded by his awesomeness, but surely you've not missed the whining about it on the left. The fact that a majority do not think the war in Afghanistan is due only to your side's failure to so convince them, not for lack of trying.
Nixon bombed North Vietnamese bases in Cambodia (and a joint US/Viet force invaded) because the North Vietnamese had invaded Cambodia and set up a large complex of bases, which due to idiots on the left we were not able to attack. North Vietnamese troops were able to slip across the border and launch attacks, conscript Vietnamese or Yards, or extort rice, then slip back before US military forces were able to respond. Failure to attack those bases in Cambodia was, with the exception of McNamara's Wall, the dumbest thing we did in a war full of dumb things. The Commies also trained, paid and equipped Communist bands in an attempt to overthrow the Cambodian government, so large parts of Cambodia were off-limits to the Cambodian government and the Cambodian people living in those areas were subject to terror, extortion, murder and conscription as workers and bearers for North Vietnamese. Perhaps you remember the Khmer Rouge and the Killing Fields - Cambodia had an even worse experience with Communism than did (and does) Vietnam. The Cooper-Church Amendment made sure no US aid or arms reached the Cambodian government, whereas leftists within the USA made sure that the North Vietnamese could safely funnel Soviet and ChiCom arms to the Kmher Rouge. Your side's success directly led to more than a million human beings, the vast majority of whom had committed no offense beyond being educated or of the wrong ethnic background, being executed directly or indirectly through a combination of starvation and forced labor. Truly it was one of the Red movement's greatest moments. Take a moment to savor the triumph before you inevitably blame America.