Forced inclusion is non-negotiable. It is the mechanism that allows users to bypass a malicious or malfunctioning sequencer by submitting transactions directly to the L1. Without it, an L2 is a permissioned sidechain.
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Why Forced Inclusion Is a Non-Negotiable Security Feature
An analysis of forced inclusion as the fundamental, protocol-enforced right that prevents sequencer censorship and ensures user exit, contrasting implementations across Arbitrum, Optimism, and Base.
introduction
THE BEDROCK
Introduction
Forced inclusion is the foundational security primitive that prevents censorship and guarantees transaction finality on L2s.
The sequencer is a single point of failure. Protocols like Arbitrum and Optimism rely on a single entity to order transactions. Forced inclusion is the escape hatch that removes this trust assumption, ensuring liveness.
This is not a theoretical risk. In 2022, a bug in Optimism's sequencer caused a 4.5-hour outage. Users with forced inclusion could have withdrawn; others were stuck. The feature defines credible neutrality.
thesis-statement
THE NON-NEGOTIABLE
The Core Argument
Forced inclusion is the fundamental property that separates credible blockchains from centralized sequencer networks.
Forced inclusion guarantees finality. A user's transaction enters the canonical chain regardless of sequencer censorship, preventing MEV theft and protocol-level blacklisting. This is the core security property that Layer 2s like Arbitrum and Optimism inherit from Ethereum.
Without it, you have a sidechain. Networks like Polygon PoS or BSC lack this property; their validators can permanently exclude transactions. This creates a centralized failure mode where a single operator dictates chain state, undermining the trustless settlement guarantee.
The counter-intuitive insight: High throughput is irrelevant if the sequencer is a single point of censorship. A user must always have the cryptoeconomic right to force their transaction on-chain, a right enforced by protocols like Ethereum's L1 for its rollups.
key-trends
WHY FORCED INCLUSION IS NON-NEGOTIABLE
The Censorship Threat Matrix
Censorship isn't just about blocking transactions; it's a systemic attack vector that undermines the core guarantees of a decentralized network.
01
The Problem: MEV-Cartel Capture
Without forced inclusion, a dominant block builder or sequencer cartel can permanently censor transactions for profit or compliance. This creates a single point of failure, turning a decentralized L2 like Arbitrum or Optimism into a permissioned system.
- Real Risk: A builder can exclude all transactions to/from a sanctioned Tornado Cash address.
- Systemic Impact: Breaks the atomic composability guarantees that DeFi protocols like Uniswap and Aave depend on.
>66%
Builder Market Share
$1B+
Protected TVL
02
The Solution: Permissionless Escape Hatches
Forced inclusion protocols, like Espresso Systems' HotShot or EigenLayer's EigenDA, allow users to bypass a censoring sequencer by submitting transactions directly to an underlying data availability layer or a permissionless operator set.
- Mechanism: Time-delayed force-inclusion queue or direct proof submission to L1.
- Guarantee: Finality is preserved, even if latency increases to ~1 week in worst-case scenarios.
L1 Final
Security Anchor
~7 days
Max Delay
03
The Problem: Regulatory Overreach as a Service
National regulators can pressure centralized RPC providers, block explorers, and stablecoin issuers like Circle (USDC). Without forced inclusion, this pressure can propagate to the chain's execution layer, enabling blacklisting at the protocol level.
- Case Study: OFAC-sanctioned Ethereum blocks post-Merge.
- Network Effect: Censorship in one service layer (RPC) can cascade to others (wallets, indexers).
30%+
Censored Blocks
Global
Compliance Risk
04
The Solution: Credibly Neutral Base Layers
Forced inclusion must be anchored to a credibly neutral settlement layer, typically Ethereum L1. This transforms censorship from a binary failure into a latency penalty, preserving the property of liveness.
- Architecture: Integrates with L1 proposer-builder separation (PBS) and EigenLayer restaking for economic security.
- Outcome: Creates a verifiable, cryptoeconomic cost for censorship that exceeds any potential profit.
L1 Gas
Cost Vector
100%
Liveness Guarantee
05
The Problem: Silent Liveness Failure
A chain can appear functional while silently excluding users. This is a liveness failure, not just a censorship event. Wallets and dApps won't detect it, creating a false sense of security for end-users and protocols.
- Stealth Attack: No failed transactions, just infinite pending.
- Trust Assumption: Breaks the fundamental promise of permissionless access.
0 Tx Fail
Stealth Metric
User Trust
Primary Casualty
06
The Solution: Verifiable Force-Inclusion Proofs
Protocols must implement cryptographically verifiable proofs that a transaction was submitted to the force-inclusion queue. This turns a subjective claim of censorship into an objective, on-chain slashing condition for sequencers.
- Tech Stack: Uses ZK proofs or fraud proofs to verify exclusion.
- Enforcement: Slashes staked capital in the sequencer's bond, making censorship economically irrational.
ZK Proof
Verification
Slashable
Enforcement
SECURITY BASELINE
Forced Inclusion: L2 Implementation Scorecard
Comparison of how leading L2s implement forced inclusion, the critical mechanism that ensures users can always exit to L1 even if the sequencer is malicious or censoring.
| Critical Feature / Metric | Arbitrum | Optimism | zkSync Era | Starknet | Base |
|---|---|---|---|---|---|
Forced Inclusion / Exclusion Opcode | ArbOS 11+ (Arbitrum One) | Deprecated (pre-Bedrock) | L1->L2 Messaging | L1->L2 Messaging | Optimism Stack |
Direct L1 Trigger | |||||
Max Inclusion Delay (Est.) | ~24 hours (Challenge Period) | N/A (Relies on L1 tx) | < 12 hours (ZK-proof lag) | < 12 hours (ZK-proof lag) | ~24 hours (Challenge Period) |
User Cost to Force Tx | L1 gas + L2 fee (refundable) | L1 gas only | L1 gas + L2 fee | L1 gas + L2 fee | L1 gas + L2 fee (refundable) |
Censorship Resistance Nuke | ✅ (Force via L1) | ❌ (Social/Governance) | ✅ (Force via L1) | ✅ (Force via L1) | ❌ (Social/Governance) |
Relies on Honest Sequencer for Speed | |||||
Implementation Maturity | Production (ArbOS) | Legacy System | Production | Production | Production (OP Stack) |
Key Dependency | Ethereum L1 Finality | Sequencer Goodwill | ZK Validity Proof Finality | ZK Validity Proof Finality | Ethereum L1 Finality |
deep-dive
THE NON-NEGOTIABLE
The Mechanics of the Escape Hatch
Forced inclusion is the foundational security primitive that prevents censorship by guaranteeing transaction execution.
Forced inclusion guarantees finality. It is a protocol-level rule that forces a sequencer to include a valid transaction in a future block, preventing indefinite censorship. This transforms censorship from a denial-of-service attack into a temporary delay, preserving the core blockchain property of permissionlessness.
The mechanism requires a direct L1 contract. Users bypass the sequencer by submitting transactions directly to a smart contract on Ethereum, like Arbitrum's Inbox or Optimism's L1CrossDomainMessenger. This contract acts as a canonical data availability layer, forcing the rollup to process the transaction in its next state update.
It is a cost asymmetry attack on the sequencer. A user pays a one-time L1 gas fee, but the sequencer must pay to process that transaction forever. This economic disincentive makes systemic censorship financially unsustainable, aligning with the security models of protocols like Across and Chainlink's Fair Sequencing Service.
Evidence: Without forced inclusion, a malicious sequencer could freeze user funds indefinitely. This is why all major rollups (Arbitrum, Optimism, zkSync) implement it. It is the minimum viable decentralization required before transitioning to a decentralized sequencer set.
counter-argument
THE SECURITY PRIMITIVE
The 'But Gas is Expensive' Fallacy
Forced inclusion is not a cost optimization; it is the fundamental security primitive that separates credible L2s from sidechains.
Forced inclusion is non-negotiable. It is the mechanism that guarantees users can always force their transaction onto the L1, making the L2's security a direct derivative of Ethereum's. Without it, you have a permissioned sidechain where sequencers can censor or reorder transactions.
Gas cost is a red herring. The debate focuses on the rare, high-cost forced transaction, ignoring the 99.9% of normal operations. The cost is the premium for an irrevocable security guarantee, similar to an insurance policy you hope never to use.
Compare to optimistic rollups. Arbitrum and Optimism implement forced inclusion via L1 inboxes. A sequencer's failure to include a transaction allows a user to post it directly to the L1 contract, penalizing the sequencer. This creates a verifiable trust assumption.
Evidence: The 2022 Optimism sequencer outage proved the feature's value. Users successfully forced transactions via the L1 during the downtime, demonstrating live fault tolerance. Without forced inclusion, the chain would have halted completely.
risk-analysis
THE FRAGILE FOUNDATION
What Breaks Without Forced Inclusion?
Forced inclusion is the cryptographic guarantee that valid transactions are processed. Removing it doesn't just degrade performance—it fundamentally breaks core blockchain security assumptions.
01
The Censorship Attack Vector
Without forced inclusion, block producers can arbitrarily exclude transactions, creating a direct path for state-level censorship and protocol-level MEV theft. This violates the base-layer neutrality that protocols like Uniswap and Aave depend on.
- Key Risk: Validator cartels can blacklist addresses or freeze assets.
- Key Consequence: $10B+ DeFi TVL becomes subject to political and financial manipulation.
100%
Censorable
$10B+
TVL at Risk
02
The MEV Extraction Black Hole
Forced inclusion is the primary constraint against maximal extractable value. Its absence turns block space into a private auction, where searchers and validators (Flashbots, Jito) capture all surplus, destroying user guarantees.
- Key Risk: Front-running and sandwich attacks become the default, not the exception.
- Key Consequence: User transaction success rates plummet as proposer-boost payments outweigh honest inclusion.
>99%
Tx Vulnerable
$1B+
Annual Extraction
03
The L2 & Bridge Time Bomb
Layer-2 rollups (e.g., Arbitrum, Optimism) and cross-chain bridges (e.g., LayerZero, Wormhole) rely on the base layer's liveness for finality and dispute resolution. Censorship breaks their security model.
- Key Risk: Malicious sequencers can't be forced out, leading to frozen funds.
- Key Consequence: Billions in bridged assets become unclaimable, collapsing the multi-chain ecosystem.
0
Safe Withdrawals
Multi-Chain
Failure Domain
04
Credible Neutrality Evaporates
Blockchains are trusted because their rules are credibly neutral—code is law. Without forced inclusion, the "law" is selectively enforced by the highest bidder, destroying this foundational property.
- Key Risk: Network forks become politically motivated, not consensus-driven.
- Key Consequence: Loss of sovereign-grade settlement assurance, reverting to trusted intermediary models.
Broken
Social Contract
Trusted
Third Parties
future-outlook
THE NON-NEGOTIABLE
The Inevitable Standard
Forced inclusion is the foundational security primitive that separates credible L2s from sidechains.
Forced inclusion is non-negotiable. It is the cryptographic guarantee that a user can force their transaction into a rollup's state, bypassing a malicious or censoring sequencer. Without it, you have a permissioned sidechain where the operator controls finality.
The alternative is custodial risk. Systems like Polygon PoS or early optimistic rollups without force inclusion functions are trust-based. Users rely on the sequencer's benevolence, which reintroduces the exact centralization problem L2s solve.
Arbitrum and Optimism implement it. They provide a one-to-many escape hatch where users submit transactions directly to L1 contracts, forcing the L2 to process them. This is the minimum viable decentralization for any credible rollup.
Evidence: The absence of forced inclusion was a critical flaw in early designs. Its universal adoption in standards like Arbitrum Nitro and the OP Stack defines the modern L2 security model.
takeaways
FORCED INCLUSION
TL;DR for Protocol Architects
Forced inclusion is the cryptographic guarantee that prevents censorship by ensuring valid transactions are eventually included in a block.
01
The Problem: Miner Extractable Value (MEV) & Censorship
Without forced inclusion, block producers can arbitrarily exclude or reorder transactions for profit, creating systemic risk. This undermines liveness and enables time-bandit attacks where past blocks are reorganized.\n- MEV Auctions: Builders can pay to censor transactions.\n- Liveness Failure: A state-level actor could blacklist addresses.
$1B+
Annual MEV
100%
Censorship Risk
02
The Solution: Commit-Reveal & Inclusion Lists
Forced inclusion protocols like Ethereum's PBS+C and Solana's Jito use cryptographic commitments to bind builders. An inclusion list is a pre-commitment to specific transactions that must be in the next block.\n- Builder Compliance: The protocol layer enforces list execution.\n- User Guarantee: Transactions with sufficient fee are unstoppable.
~12s
Guarantee Window
0
Exclusion Slots
03
The Trade-off: Latency vs. Guarantees
Forced inclusion introduces a latency penalty for the guarantee. The system must wait for the inclusion list to be published and verified before finalizing the block. This is a core design tension with high-frequency trading (HFT) DeFi applications.\n- Throughput Impact: Adds 1-2 slot delay for censorship resistance.\n- Non-Negotiable: The security property is worth the marginal latency cost.
+1 Slot
Latency Cost
100%
Liveness Gain
04
Implementation: Ethereum's enshrined PBS
Ethereum's path via EIP-7547 and PBS makes inclusion lists a core protocol feature, not an add-on. This removes trust from builders/relays and places it in the consensus layer. Contrast with out-of-protocol solutions like Flashbots SUAVE, which introduce new trust assumptions.\n- Enshrined > Ad-Hoc: Protocol-level guarantees are irreversible.\n- Builder Diversity: Prevents relay cartels from controlling access.
L1 Native
Trust Model
All Validators
Enforcement
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