In the Pennsylvania Senate primary on Tuesday, Mr. Trump supports Dr. Mehmet Oz, the longtime television personality. Meanwhile, the Club for Growth endorsed Ms. Barnette, a conservative author and political commentator who has surged in the polls. In the Alabama Senate contest next week, Mr. Trump rescinded his endorsement for Representative Mo Brooks, while the Club for Growth has stood by him.
Still, the Club for Growth and Mr. Trump were on the same side in a contested West Virginia House primary this month. In that race, their support for Representative Alex Mooney helped him coast to an 18-point victory over his House colleague David McKinley, who had support from much of the state’s political establishment. The Club for Growth spent more than $1 million in that House race, twice as much as any other outside group.
With two more weeks remaining in the first full month of primary contests this year, the Club for Growth super PAC has already spent $32 million on federal races. That’s twice as much as any other outside group and already half of what the group spent in the 2020 election cycle. In recent years, much of the super PAC’s funding has come from Uline Inc., a shipping company owned by Dick and Liz Uihlein, and Susquehanna International Group, an investment company co-founded by Jeff Yass.
In 2016, the Club for Growth endorsed Mr. Budd and spent $500,000 to help him emerge from a crowded primary. The Budd family later donated at least $50,000 to the group.
This year, the group has spent $11 million supporting Mr. Budd, roughly 57 percent of the outside spending in the Republican Senate primary.
Heading out of her local polling place during early voting on Thursday, Cyndi Glass, 63, said she was aware of just two Senate Republican candidates. One was Mr. McCrory, but she said she “wanted something different.”
The other was Mr. Budd.
“Trump endorsed him,” she said. “And that was a plus for me.”