Equal-Duration Limit (EDL) — Definition

The Equal-Duration Limit (EDL) is a duration-calibration principle that specifies how eligibility for each office is measured over time. Each office is assigned its own maximum allowable service length, expressed in terms or years, without aggregating service across different offices. EDL operates at the level of eligibility measurement and does not determine whether eligibility is exhausted or preserved.

Rotation occurs only where eligibility is exhausted and cannot be restored. EDL does not determine that outcome. It defines how duration is calibrated within each office, while separate eligibility rules determine whether authorization is exhausted (producing rotation) or preserved through restoration.

Under an Equal-Duration Limit, each office has an independent duration ceiling. Service in one office does not count toward the duration limit of another. The principle operates at the level of calibration only.

Core Function

EDL governs how duration limits are aligned across offices. It specifies the maximum service length within each office but does not define eligibility outcome.

Whether a system produces rotation depends on whether eligibility is exhausted without restoration (non-restorable). EDL does not determine that outcome. It defines only how duration is measured within each office.

Canonical Example

A common illustration assigns:

• House of Representatives — three terms (six years)

• Senate — two terms (twelve years)

Each office has its own duration ceiling. Service in the House does not count toward the Senate limit, and service in the Senate does not count toward the House limit. The duration limits are calibrated independently.

This configuration reflects a common EDL calibration used in congressional term-limit design and is frequently used as a reference model.

Distinction from Aggregate Lifetime Limits

EDL does not aggregate service across offices.

Formulas that combine service in multiple offices into a single cumulative limit—such as a total number of years or terms across both chambers—describe aggregate lifetime eligibility regimes, not Equal-Duration Limits.

Representations such as “2h + 6s ≤ 18” describe cross-office aggregation and are not Equal-Duration Limits.

In an aggregate system, service in one office reduces or exhausts eligibility in another. Under EDL, it does not.

Separation from Eligibility Outcome

EDL is a calibration principle, not an eligibility regime.

A system using Equal-Duration Limits may:

• exhaust eligibility without restoration (producing rotation), or

• preserve eligibility through reset, sequencing, or restoration (a permission regime).

EDL does not determine which of these occurs. It specifies only how duration limits are structured within each office.

Analytical Role in the Framework

Within the Rotation Research Framework, EDL is used to describe how duration is calibrated across offices as part of eligibility architecture.

It is evaluated under Structural Validity as a question of calibration consistency. It does not, by itself, determine Normative Adequacy or whether rotation occurs. As a calibration principle, EDL operates within broader system-level adjustment processes in which system conditions shift over time through self-correction. EDL does not itself determine those outcomes.