I’d say the anti-paternalists win the debate in theory but the libertarian paternalists win it empirically. In theory, it is possible that gentle nudges will turn into intrusive diktats and the nanny state will drain individual responsibility.
But, in practice, it is hard to feel that my decision-making powers have been weakened because when I got my driver’s license enrolling in organ donation was the default option. It’s hard to feel that a cafeteria is insulting my liberty if it puts the healthy fruit in a prominent place and the unhealthy junk food in some faraway corner. It’s hard to feel manipulated if I sign up for a program in which I can make commitments today that automatically increase my charitable giving next year. The concrete benefits of these programs, which are empirically verifiable, should trump abstract theoretical objections.
I’d call it social paternalism. Most of us behave somewhat decently because we are surrounded by social norms and judgments that make it simpler for us to be good. To some gentle extent, government policy should embody those norms, a preference for saving over consumption, a preference for fitness over obesity, a preference for seat belts and motorcycle helmets even though some people think it’s cooler not to wear them. In some cases, there could be opt-out provisions.