Why is US not invading Pakistan? Are we not superpower?

They give shelter to Laden. INVADE! If we can invade iraq and afghanistan, then why not Pakistan too? We are superpower. Remember we invaded iraq because they had WMD. The REAL WMD exist in Pakistan because they have 100 nukes. And with al-qaeda finding safe haven there, those nukes can easily be handed to AQ. So this is even stronger case of invasion. I say we should invade them by element of surprise and even though its well known some of our troops will get killed by their nukes, we still have huge population of 310 million. So there's no shortage of troops. Obama should take the opportunity and INVADE. Let's do it!