1) The U.S. thought Saddam had nukes and that didn't stop the invasion of Iraq.
2) Napoleon never dreamed of going to war for oil - the modern-day French obsession, expressed numerous times since at least 1990.
3) Pursue WMDs and one risks Pakistan's fate: poverty from diverted resources, radio-chemical pollution from a dangerous industry, electricity shortages due to consumption by uranium enrichment plants, and finally civil war as "Islamic" militant groups, seeing vast power ready-to-grab, start by intimidating the populace, then officialdom, then finally the soldiers in their battle for power.
For in Islam many people want the privilege of imposing Sharia law on others for they are then free to not follow it themselves - isn't that so? That's very close to how the M-B has justified Mubarak's tyrannical rule in Egypt.