Barack Obama the student activist and Barack Obama as US President I suspect are two very different political animals. Barack as student activist would no doubt be totally opposed to US forces being in Afghanistan, President Obama is piling more forces in because he says the US isn't winning. In that respect he isn't very different from Lyndon Johnson.
As for Brezhnev's wet dream, well that was Harold Wilson - until Wilson became Prime Minister and MI5 told him how the Soviets were spying on him....
As I understand it, he is carefully weighing the military and political situation and trying to determine whether Afghanistan is worth a lot more US lives and treasure. The greatest problem is the government there is pretty thoroughly corrupt and isn't really supported by the majority of the people, who don't see it helping them much. Big parts of the country are controlled by warlords whom the government doesn't really dictate to. Then we have the Taliban, and while they are strict Islamic fundamentalists and suppress women, not all Afghanis see that as a problem. They weren't nearly as corrupt as the current regime and suppressed the drug trade until they needed the money to fight us. Then you have the US populace, who don't necessarily support our presence there, and the other countries of the world, who don't seem to care much one way or the other.
If you can't solve some of these fundamental problems, having a powerful military on the ground there still isn't going to win. We won every major battle in Vietnam, but still lost the war. It cost us the lives of 50,000 young men and ripped apart our political fabic, which still hasn't healed. Some people think that if you just blow up enough stuff, that's all it takes. Maybe that's true if you have enough soldiers and want a huge empire and your moral outlook allows slaughtering enough people out of hand, but that's not the USA. That's Ghengis Khan.