A former national security adviser to President Trump has thrown his hat into the ring for retiring Oklahoma Sen. James Inhofe’s seat. Alex Gray, who served as the National Security Council chief of staff, announced his campaign on Tuesday and has already scored an endorsement from former acting Director of National Intelligence Richard Grenell.

The Hill reports:

“The current 50-50 split in the Senate is terrifying, and we must keep the seats we have and add additional ones in the 2022 election cycle. Republicans in the Senate are the last line of defense against court-packing, the green new deal, radical liberal judges, and 40 year-high inflation under the Biden administration,” Gray said in a statement.

“I was honored to serve President Trump every day of his presidency in the White House, and I will continue President Trump’s America First mission in the Senate and fight for the same conservative policies that helped our country prosper under his leadership,” he continued. “I am looking forward to introducing myself to the people of Oklahoma and sharing our vision not only for Oklahoma but our country’s future.”

Inhofe, 87, formally announced late last month that he would be retiring from his Senate seat at the end of the year, and that he is endorsing his chief of staff Luke Holland to replace him.

“As a fourth generation Oklahoman, I know America is the greatest country in the world. It’s a gift from God, and that’s why we must do everything we can to stop the march toward socialism, stand up to China, and get President Trump’s agenda back on track,” Holland said on his campaign website.

Gray is expected to face a crowded field of challengers for the Senate seat.