No crap there are holes in Scenario B. Why don't you describe one that would be realistic since you seem to be good at looking at the details? I gave you all sorts of links about missing plagues and other bomb-making materials.
Or maybe the terrorist's just put up a sign at the launchpad that says "Acme Oil Drilling, Serving Des Moines since 1897!"
Regardless, Article 1 Section 8 of the Constitution lists one of the duties of the federal government as "repel Invasions". An invasion occurs when someone or some group enters the land as an enemy and any activity to prevent or discontinue that situation would constitute repelling.
Additionally, Article IV Section 4 says "shall protect each of them [State in the Union] against Invasion".
I know the 4th Amendment talks about being secure in your papers and effects against searches, but this NSA surveillance (from what I've read) seems to be reasonable, warranted, and used in a limited manner (given that the real economy is still in a slump and new politicians get elected to existing posts).
Please try explaining to me again how the NSA looking for potential high-impact terrorist events is not a valid and important government function.