The current "old" nukes are in need of replacement because of a number of different reasons.
#1. Guidance packages have been developed that ensure an even better amount of accuaracy (less than the 100 meters) the current Tridents warheads offer.
#2. Rockets, especially solid fuel rockets deteriorate with age. So, they need to be replaced. Also, better technology allows for smaller systems which in turn can limit the size of rocket needed and it's abilities to evade launch detection.
#3. The warhead itself. Given the fact that the fissile material in a warhead is highly radioactive, the shielding is constantly being bombarded with high level radiation, and is constantly breaking down, and creating a danger over time that the electronics and wiring needed to start the reaction are damaged. So, that also needs to be replaced. Technology grows and can alos limit the blast, as well as produce a more efficient blast.
As for the need to maintain a nuclear stock pile, I feel it to be a worthwhile, but unfortunate cause. I think MAD is accepted among the mature nations enough that we need not worry about blowing our enemy up 30 times over and can suffice with 3 or 4 times over though. As for the "rogue states" who maintain programs to attain nuclear weapons, that is are biggest worry. Sadly, MAD does not mean much to those rogue state's governments though.
As for the 1st strike ability, or pre-emptive strikes in dire need, I guess I suppport it if the need demands that type of reaction. IE. OBL is about to release a doomsday virus and we have valid intel that he is in "insert a cities name" then, I think for the good of man kind, it would be smart to do. But God need to provide mercy upon the one who makes that decision. All in all, this decision is a tough one to make, and one all of us are not able to make as we are not informed to the level one needs to be to make decisions on national and global security.
This brings up one other thing, neither is Kerry, as ole Herman never goes to intel briefings.....

good choice for president he is...
