Why an SSBN is not the modern battleship

Are ballistic-missile submarines the modern equivalent of battleships?

No; an SSBN deters strategically through concealment and assured retaliation, while battleships combined visible conventional coercion with strategic weight - a role now closer to an aircraft carrier.

The comparison turns on how a ship produces deterrence. A ballistic-missile submarine preserves a retaliatory strike by remaining hidden, so its principal value lies in an opponent's inability to destroy it before it can respond. A battleship could instead appear visibly and threaten conventional force, while also carrying strategic weight. Aircraft carriers are offered as the closer modern equivalent because their presence and aircraft provide that visible conventional option. Another panelist extends the comparison to some large surface combatants, with Sejong the Great used as an example of concentrated missile capacity.