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Union political spending: results from ballot measures, bills, and elections

We examined $175.4M in union ballot-measure spending across 12 states, 5,361 candidates, and 55 within-party legislative comparisons. Union-backed sides won most measures, and funded legislators sponsored more pro-labor bills. Differences in bill passage and floor voting were much smaller; close-election results varied by state.

Five outcomes examined

Union-backed sides won 33 of 49 measures

We searched twelve states' campaign-finance records from 2014 onward for committees campaigning on named ballot measures. 54 committees received $175.4M in union contributions. Forty-nine measures had been decided.

“Won” and “lost” describe the union’s side, not the measure. On four of these six, the union was campaigning against a measure, so a rejected measure is a win. Share of the campaign is union money as a proportion of everything that committee raised. Each measure links to its full background; results can also be looked up at California’s Secretary of State and Washington’s results archives.

Labor funded 94.8% of the No campaign on Proposition 22, roughly $18M. App companies outspent that campaign about ten to one, and the measure passed with 59%. Proposition 15 received the largest union contribution total in the dataset, $35.8M, or two-thirds of its campaign's funding. It failed by four points.

The win rate and spending totals describe different aspects of the record. Union-backed sides won most measures, but substantial contributions also went to losing campaigns.

Funded legislators sponsored more pro-labor bills

We compared legislators who received union contributions with unfunded legislators of the same party in the same chamber, counting the pro-labor bills each introduced as primary sponsor.

Funded legislators sponsored 1.44× as many bills overall and 4.17× as many pro-labor bills. In all 10 cases tested, the difference in pro-labor sponsorship exceeded the difference in overall sponsorship. General legislative activity alone did not account for the gap.

We count primary sponsors, the legislators who introduce bills. We exclude cosponsors who add their names to someone else's bill.

Bill passage rates were similar

The difference in sponsorship was much larger than the difference in passage rates.

Within individual comparisons, funded legislators' passage rates averaged +5.2 points above their colleagues' for other bills and −8.8 points below for pro-labor bills. These averages differ from the pooled rates above.

One possible explanation is that funded legislators introduce more ambitious pro-labor bills or face chambers less willing to pass them. This analysis does not test those explanations.

Bill introduction can put a position on the record and contribute to later legislation. Those outcomes fall outside the passage-rate comparison here.

Floor voting differed by about two points

We also compared final-passage votes to see whether funded legislators voted in the pro-labor direction more often than unfunded colleagues.

We compare legislators within parties because Democrats and Republicans differ substantially in their labor voting records, and most union contributions go to Democrats. A comparison across parties would conflate that party difference with the funding relationship.

The difference was small relative to the gap in bill sponsorship, though a few votes can matter in a closely divided chamber.

Close-election results varied by state

We matched union contributions to 5,361 candidates in the six states where campaign-finance records could be joined by name to certified results. We then compared outcomes in races decided by fewer than ten points.

State estimates span 42 points. Washington has the longest campaign-finance history in the comparison and provides its own certified results export; it shows little difference in close-race win rates. The three largest differences come from the three smallest samples.

The largest sustained bet on a single candidate anywhere in the file sits outside those six states. The Chicago Teachers Union gave $5,487,921 to Friends of Brandon Johnson between February 2019 and January 2025, on the Illinois State Board of Elections disclosure record; Johnson, a former CTU organizer, won the Chicago mayoralty in April 2023 with 51.4%.

The clearest legislative association was with sponsorship

For unions assessing their spending, sponsorship and passage need separate measures. Funded legislators introduced more pro-labor bills, but those bills passed at a similar rate to bills from unfunded colleagues. This study does not determine which spending strategy would improve passage.

The roughly two-point difference in floor voting is consistent with unions funding legislators who already share their priorities. The comparison cannot establish whether contributions changed anyone's votes.

How this was built

Whose money

Form LM-2 filings from the Labor Department’s Office of Labor-Management Standards, which every union above $250,000 in annual receipts must file. The fiscal-2025 file we worked from holds 4,599 LM-2s. Locals are ranked on the dues they spent on political activity, not on their PAC. The two are legally separate pots — federal law bars dues money from funding federal candidates.

Where it went

Campaign-finance filings from twelve states — Washington, Illinois, California, Arizona, New York, Massachusetts, Oregon, Maryland, Michigan, Ohio, Minnesota and Pennsylvania — plus the Federal Election Commission. Committees are matched to unions from the committee’s own registered name rather than the FEC’s affiliated-organization field, which is unreliable enough to label a national fund after a single local branch.

What the legislators did

Bills, primary sponsorships and recorded floor votes from LegiScan. 1,969 bills were classified by direction — 575 pro-labor, 54 anti-labor, 1,340 neutral. That direction is our judgement, from keyword rules plus a model reading the bill, and it is not a record of any union’s stated position on any bill.

Who won

Candidate outcomes use certified returns from Washington’s own certified export and OpenElections for Arizona, California, Oregon, Michigan, and New York. Each ballot-measure outcome was checked separately and assigned a source.

The comparison

Every result compares union-funded legislators with unfunded ones of the same party in the same chamber. One comparison is one union in one state, split by party; there are 55 of them. A candidate who stood in more than one of these elections is counted once for each. Where a state’s campaign-finance record begins later than its election results, the earlier years are dropped rather than scored — otherwise every candidate in those years reads as unfunded.

What this cannot tell you

Association, not cause

Every result here is an association. Nothing in this data shows that spending caused any outcome.

Funding may follow sponsorship

Unions may contribute to legislators because those legislators have sponsored pro-labor bills. The observed relationship is consistent with that explanation and does not establish that contributions produced the sponsorship.

What a win rate can’t tell you

A union chooses which fights to enter. Two in three is partly a statement about the measures they picked, not only about the money they spent. Unions also turn up on both sides of the same question: they funded the yes and the no campaigns on California’s Proposition 30 in 2022 and Proposition 36 in 2024, and on the two rival death-penalty measures on the same 2016 ballot — in that case police associations against everyone else.

Geographic coverage

The twelve states were selected because their campaign-finance records were available to us. Six could be joined to certified candidate results. The sample is not random and does not describe the other thirty-eight states.

Limited coverage of spending

Across these six states, only 6% of union political giving — $126M of $2.04B — reaches a state legislative candidate at all. The rest goes to governors, mayors, city councils, judges, ballot committees and other unions’ own funds, none of which we can score against a legislative record. Part of that $2.04B is also transfers between union committees rather than giving. Everything in this article describes the sliver of union political money that is scoreable, not the whole of it.

Bill classification

Whether a bill is pro-labor, anti-labor or neutral is a keyword-and-model classification made by us. A union that considered a given bill unhelpful will not have been consulted, and no union’s stated position enters the calculation.

Limited passage evidence

Only three union-and-state comparisons met our evidence threshold for passage: operating engineers in Washington, service employees in New York, and electrical workers in Maryland, all among Democrats. That is too few to reach a firm conclusion about the relationship between funding and bill passage.

No optimal spending amount identified

An apparent best-performing spending range did not hold up after checking for campaign size and California's influence on the results. We could not identify a reliable optimal amount.

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