So lets say the government or Israel DID do all of the above (which they didn't but I'm playing along). The point is that "they" would do all of that---dozens of violations of the law, trust, decency, etc....--and then turn around and NOT plant a WMD or two in Iraq or Afghanistan to justify the war, the billions spent (and the billions to spend in the future) and the lives lost?
This I think may be pretty simple to understand: Since I don't think 9/11 was some massive cover-up with numerous levels and hundreds of people covering things up it was actually easy to accomplish. Considering the official story is that a few terrorists with box-cutters took over planes and flew them into buildings how hard is it to conceive that a couple CIA agents led them to do it? Which leads me to....
Planting a WMD in Iraq or Afghanistan would involve numerous military officials, and probably some soldiers who would not be involved in some sort of cover-up. We've seen all the generals and soldiers who have come to expose what is really happening in the middle east. We've seen people admitting killing civilians. We've seen the cover-up exposed in Pat Tillman case.
Many of the people involved in the lead up and war in the middle east got what they wanted I believe, and trying to cover that up where numerous people would have to be involved, including what I believe would be lower level soldiers I think the risk of getting it exposed was too great.