I would be against it in the same way I was opposed to it when it was proposed by Bush.
Let me see if I understand this correctly: Don't like the Patriot Act because it can be used for purposes that we don't understand; BUT, you're okay with monitoring phone calls and records, which is an extension of the Patriot Act and is advertised exactly like the Patriot Act was (deterrence against terrorism), and which most likely will be used for purposes that none of us fully understand....
It's not okay to have our mail carriers monitor us, but it is okay to have our cell phone providers help the government monitor us....
Agh. Where's the Excedrin? My head hurts....
BTW: If you want to keep the terrorists from using cell phones, then discontinue the ability of cell phone carriers to sell "pay as you go" phones that can be paid for with cash or anonymous gift cards, be easily discarded, and are extremely hard for the government to track. You don't need to download hundreds of millions of Americans' phone records if you've made it where the only way you can use a cell phone is to actually put your name on an account. While not 100% full-proof (nothing is), it would go a long way towards negating the use of cell phones for illegal activities.
AND, this worry about more 9/11 attacks? I'm more worried about being rear-ended by a teen-ager with a suspended license and no insurance ... wait, that happened last Saturday....