Robert Lighthizer, who served as U.S. trade representative during the Trump administration, endorsed J.D. Vance’s Ohio Senate campaign Wednesday, throwing more Team Trump support his way.

Lighthizer in a statement cast the “Hillbilly Elegy” author and venture capitalist as a champion for the working class and the Trump administration’s economic policies.

“JD will advocate for our working-class and work to rebuild our country’s industrial base by continuing President Trump’s America First foreign policy that renegotiated trade deals and held big corporations accountable. He will stand up to China, which already has its claws in our tech industry and will fight for the forgotten communities of Ohio whose jobs were shipped overseas. He is the strong leader that Ohio needs in the U.S. Senate,” said Lighthizer.

The endorsement comes about a week after Vance also won the endorsement of Robert O’Brien, former President Trump’s final national security adviser.

The dual endorsements could boost Vance in a crowded GOP primary that has been framed by the contenders’ loyalty to Trump, who remains wildly popular with the Republican grassroots. 

Vance is one of five Republicans running in the primary for the open seat being vacated by Sen. Rob Portman (R).

In a sign of the role Trump has played in the nominating contest, Kellyanne Conway, a senior counselor in the Trump administration, is advising businessman Bernie Moreno, and Vance’s opponents have panned him over past comments criticizing Trump.

Vance first rose to prominence in 2016 after authoring his best-selling memoir on his upbringing in Appalachian Ohio, which observers cast as a unique insight into the voters living there. 

“President Trump gave Ambassador Lighthizer perhaps the most important job in American economic policy, and he did a great job for our president and country. I'm honored to have his support, and I'll be thrilled to rely on his counsel when I get to the Senate,” Vance said of Lighthizer’s endorsement. 

Other Republicans running in the primary include Moreno, former state Treasurer Josh Mandel, businessman Mike Gibbons and Jane Timken, the former head of the Ohio Republican Party. 

Rep. Tim Ryan and progressive activist Morgan Harper are running in the Democratic Party, though Republicans are expected to enjoy an edge in the general election in a state that has shifted toward Republicans in recent years.