[cameldrv]

Accurate SLBMs, possibly on depressed trajectories. Russia didn't have these in numbers at the end of the cold war, now they do. They have even added GLONASS guidance to their ballistic missiles, which is worrying, because it means that they care about accuracy while GLONASS is still working, i.e. in a counterforce first strike.

Given the time it may take to validate and characterize a launch warning, have the message reach the President, have him make a decision, relay the message through STRATCOM, retarget the missiles (assuming we're still detargeted), and launch, you're talking at least 10-15 minutes from warning to launch. The Russians have missiles that might arrive faster than that. If bombers on the ground are maintained at a high enough level of alert, they can be launched at the very first warning as a precaution, before any irrevocable decision has been made.

[mikeash]

That makes some sense. Do the numbers work out, though? You could launch bombers on a less certain warning, but they'll take longer to get far enough away to be safe.