Mining pools can and do enable transaction censorship because miners typically delegate block construction to pool operators or external builders, concentrating gatekeeping power over which transactions are included. Mining pools aggregate hashing power to reduce variance in rewards, and in doing so many miners accept a block template supplied by a pool operator rather than constructing blocks themselves. Research by Ittay Eyal and Emin Gün Sirer at Cornell University demonstrated that such centralization of mining incentives creates strategic points of influence over consensus behavior, including transaction selection. Arvind Narayanan at Princeton University and coauthors in Bitcoin and Cryptocurrency Technologies describe how this delegation shifts practical control of the ledger from dispersed hashpower to a smaller set of decision makers.
Mechanisms that enable censorship
At the technical level, censorship can arise because a pool operator or an upstream block builder determines the block template and the ordering of transactions. Block template control lets the operator exclude particular transactions, deprioritize fees for certain addresses, or insert private transactions ahead of public ones. This is not merely hypothetical; the emergence of private transaction relay networks and miner-extractable-value marketplaces has already changed the incentives around transaction ordering. Organizations studying MEV and private relays such as Flashbots have documented how private bundling and direct submission channels allow some transactions to bypass or be hidden from the public mempool, which can facilitate selective inclusion or exclusion.
Causes, relevance, and consequences
Economic pressure, legal risk, and centralized service arrangements are primary causes that make censorship more likely. Large pools operate across jurisdictions and may comply with local regulations or sanctions to avoid legal exposure, leading to voluntary filtering of transactions. Small miners selling their hashpower for predictable rewards have limited leverage to oppose such policies. The practical consequence is a weakening of censorship resistance, a core property many users rely on for political speech, remittances, and financial autonomy. Targeted censorship can harm dissidents, journalists, and cross-border economic activity where access to uncensorable payment rails is essential. Environmental and territorial nuances matter because mining has historically concentrated in particular regions at different times, creating localized leverage for regulators or infrastructure providers to influence or pressure pool operators.
Mitigations exist but are imperfect. Redistributing block-construction authority via decentralized pool designs, encouraging solo mining, or adopting protocol-level changes to separate proposers from builders have been proposed and debated in academic and developer circles. Each mitigation carries trade-offs in efficiency, security, and likelihood of adoption. The literature and practitioner reports from researchers at Cornell University and Princeton University, and technical groups studying MEV such as Flashbots, provide documented analysis showing that while mining pools improve economic stability for miners, they also create realistic pathways for transaction censorship unless countered by design, governance, or diversified participation.