What Is the “Nothing-at-Stake” Problem and How Do PoS Protocols Address It?

The "nothing-at-stake" problem is a theoretical issue in early PoS designs where validators, facing a chain split, have no cost to validate on both competing chains. This could prevent the network from reaching consensus.

Modern PoS protocols solve this by implementing 'slashing,' which penalizes validators who sign blocks on multiple competing chains, thus creating a financial cost to misbehavior.