> rendering the power of MAD and military alliances close to negligible
Are you implying you can destroy the enemy's nuclear arsenal in your first strike? If so, you don't understand MAD. Any submarine arsenal will be nearly impossible to destroy. If you first strike North Dakota (for example) to destroy all the missile silos, subs will simply eradicate your country.
I understand MAD. But "nearly impossible" is not impossible (think not only nuclear, but the whole arsenal of modern weapons, including computerized, chemical, biological etc). The problem is not actual first-strike capability though, it is perceived such, be it one's own or the enemy's.
The whole premise of submarine nuclear strikes is that:
A single submarine cannot be trivially located - the ocean is too deep and vast. If countries working together can't find the wreckage of a single crashed airplane in a generally known location, how do you expect them to find dozens of cloaked subs in unknown locations each holding hundreds of nuclear warheads?
Even assuming you wipe out 100% of the continental USA's weapons with a first strike, there are still thousands of nukes in the ocean ready to wipe your country off the face of the earth.
How does this fit in with your original argument that first strikes "render the power of MAD and military alliances close to negligible"?
I find it interesting that your examples involve the case where the US is under attack. Let's turn it round: do you find it equally implausible that the US would not believe they have a capacity to thwart the second-strike capacity of say, North Korea? I'm not saying this is more realistic, I'm saying it is this perception of first-strike capability that is dangerous, and any country can believe themselves to be invincible, not just the US.
Are you implying you can destroy the enemy's nuclear arsenal in your first strike? If so, you don't understand MAD. Any submarine arsenal will be nearly impossible to destroy. If you first strike North Dakota (for example) to destroy all the missile silos, subs will simply eradicate your country.