It lists every endorsement he has collected in his bid for Congress, but one name sits alone at the top, printed larger than the rest: Josh Shapiro. For Brooks, a firefighter union president making his first run for office, the Pennsylvania governor’s backing is the centerpiece of his campaign, splashed across television ads, fliers and the homepage of his website.

“Having him on everything for me, in the videos, the commercials, the fliers, I think it’s very important to the race,” Brooks said in a recent interview. “Because people trust him. And if he trusts me, it just trickles down.”

The May 19 primary will decide who challenges Republican Representative Ryan Mackenzie in one of the nation’s most competitive House districts. But for Shapiro, a potential White House contender, the race has become something more: a test of whether his political coattails can carry a novice candidate through a crowded field and into a general election that could help Democrats flip control of the House.

Shapiro helped recruit Brooks, a longtime ally who leads the state’s largest firefighters union, into the race. His endorsement lifted Brooks from relative obscurity to the front of a four-way field in some polls and unlocked a wave of outside spending that his opponents have struggled to match. The governor is working to flip up to four House seats in Pennsylvania this cycle, and Brooks represents one of his most direct investments.

But the bet carries risk. Brooks holds only a slim lead in the most recent survey and trails in fundraising, suggesting limits to Shapiro’s influence. His intervention in the primary has also irritated some influential local Democrats, who have publicly aired their grievances about the governor’s choice to back a political novice over more established candidates.

The campaign recently drew unwelcome attention when Brooks said in an interview that Shapiro had asked his union to endorse the Republican state treasurer over her Democratic rival in 2024 because of a personal grudge. Both Brooks and Shapiro’s team later said the remarks were inaccurate, but the episode underscored the scrutiny that follows a governor with national ambitions.

Shapiro, who is expected to win reelection easily this year, is using the race to demonstrate his ability to deliver results in the nation’s biggest swing state. A strong showing for Brooks in the primary and a victory in November would bolster the governor’s reputation as a kingmaker. A loss would raise questions about the durability of his political brand.

For now, Brooks is leaning heavily on the governor’s name. His handouts carry Shapiro’s signature at the bottom. His advertisements open with the governor’s face. And on the campaign trail, Brooks tells voters that if Shapiro trusts him, they can too.