MONTGOMERY, Ala. (AP) — U.S. Sen. Richard Shelby endorsed former chief of staff Katie Boyd Britt in the GOP primary for his Senate seat.

In comments to Politico, he called her the best-qualified candidate to come along in a long time. Shelby is retiring at the end of his term, igniting a competitive GOP primary for the nomination in the red-leaning state.

Britt so far is in a three-way race for the GOP nomination along with U.S. Rep. Mo Brooks and businesswoman Lynda Blanchard, who was former President Donald Trump’s ambassador to Slovenia. Trump in April endorsed Brooks in the race.