Ethereum co-founder Vitalik Buterin has called for fresh measures to protect the network’s neutrality, warning that overreliance on a small set of block builders could expose the blockchain to censorship risks.
In an August 22 post on X, Buterin outlined three steps to strengthen Ethereum’s resilience: improving the public mempool to avoid transaction bottlenecks, building distributed block-construction systems, and creating fallback channels to ensure transactions are eventually included on-chain.
Buterin’s Proposal: Fork-Choice Enforced Inclusion Lists (FOCIL)
At the heart of Buterin’s plan is a mechanism called Fork-Choice Enforced Inclusion Lists (FOCIL).
Instead of relying on a single block proposer per slot, FOCIL would designate 17 proposers. One proposer would still set transaction order, but the other 16 would act as auxiliary validators, ensuring that their chosen transactions are included in the block.
“The goal is to prevent a block builder oligopoly from having a veto over transaction inclusion,” Buterin explained.
This design could also extend to smart contract wallets and privacy tools, reducing Ethereum’s dependence on centralized intermediaries. Importantly, the auxiliary proposers would have a lighter role than the lead proposer, making participation accessible to more validators.
Pushback: Legal Risks and Practical Concerns
Not everyone is convinced. Ethereum developer Ameen Soleimani argued that FOCIL could backfire, especially for U.S.-based validators subject to sanctions law.
He pointed to the case of Tornado Cash, where nearly 90% of validators once avoided processing its transactions. Although this slowed confirmation times, it still allowed them to clear without forcing validators into potential legal jeopardy.
FOCIL, Soleimani warned, would change that dynamic by requiring validators to include flagged transactions. That could expose them to prosecution or asset seizure by U.S. regulators.
“If I was the US gov, I would actually be 100% in favor of FOCIL,” he wrote. “You mean to tell me the ETH validators are all going to be forced to incriminate themselves by validating blocks with sanctioned address txns? Well great, that means I can go after any ETH validator on US soil whenever I want.”
Soleimani also questioned whether the system would work in practice. Currently, controversial transactions get processed because some validators act out of altruism, but FOCIL lacks clear incentives or protections to balance the risks.
What’s at Stake
The debate highlights Ethereum’s ongoing struggle to balance decentralization, neutrality, and compliance in an increasingly regulated environment.
For Buterin, FOCIL represents a way to keep the network censorship-resistant and aligned with its founding principles. For critics, it risks drawing validators into direct conflict with regulators and undermining Ethereum’s long-term sustainability.
As Ethereum continues to evolve, the community faces a crucial question: how can the network preserve its neutrality without putting its participants in legal crosshairs?
