Which states have seen the largest decrease in Republican voter registration in the past year?

1. The question being asked, and why the sources fall short

The user asks for the states with the biggest declines in Republican registration over the last year, which requires state‑level, year‑over‑year partisan registration tallies; the sources here either present national aggregates, multi‑year analyses, or highlight Democratic losses and Republican gains rather than enumerating states with Republican declines ^{[3] [1] [2]}. Several official outlets update monthly (e.g., Colorado’s Secretary of State provides monthly files) but most summarized reports cited in the search do not publish a simple “largest Republican decline” table for the recent 12 months, and some states don’t disclose party registration data at all or lag in updates ^{[4] [3]}.

2. What the available reporting does show about partisan registration shifts

Multiple analyses reported that Democrats lost registration share in a broad set of states between 2020 and 2024 while Republicans gained in many of the 30 states that track party on registration forms, a pattern repeated in national summaries and commentary ^{[1] [2]}. The New York Times‑cited analysis noted Democrats declining in every one of 30 tracked states between the two presidential cycles, and follow‑up commentary emphasized Republicans picking up some of that ground and a rising “no party” cohort ^[2]. Pew’s broader partisanship polling documents shifts in partisan identity over time but does not provide the state‑by‑state registration deltas the question requires ^{[6] [7]}.

3. Examples and counterexamples from specific states in the record

California reporting highlighted increased Republican registration among younger voters and a measurable shift in some demographic groups that reduced the Democratic margin, signaling at least localized Republican gains rather than GOP declines ^[8]. North Carolina analysis illustrates a cautionary counterpoint: the state’s story was not Republican growth but Democratic decline and Republican stability — Republicans in that reporting remained roughly where they were decades ago, underscoring that changes can reflect one party shrinking rather than the other growing ^[9].

4. Transparency, data access and why precise answers are elusive

State reporting practices vary widely: some states do not track party on registration or do not publish up‑to‑date summaries (Arkansas, Connecticut, Hawaii, Indiana, Missouri, North Dakota, Ohio and Tennessee were listed as not having released 2025 data in one compilation), and the Justice Department’s recent litigation over voter data access further complicates centralized analysis of raw registration rolls ^{[3] [5]}. Where secretariats do publish timely monthly files (e.g., Colorado), researchers must still assemble and normalize disparate formats to compute consistent year‑over‑year Republican registration changes ^[4].

5. Bottom line conclusion and next steps for a definitive ranking

Based on the provided sources, it is not possible to say which specific states have seen the largest decrease in Republican voter registration in the past year because the reporting emphasizes Democratic losses and broad shifts across cycles, state disclosures are inconsistent, and the necessary state‑level, year‑over‑year Republican registration tables are not contained in these sources ^{[1] [2] [3]}. To produce the requested ranking would require collecting the most recent official monthly or annual registration files from each state that records party affiliation (or a trusted aggregated database that publishes year‑over‑year Republican counts), then calculating the net changes per state — a step suggested by the presence of state files like Colorado’s but not provided in the current documents ^[4].