The rule I've always used is that if the first letter of the word immediately following it is a vowel, it's "an" and if it isn't use "a".
For example, "an apple" or "a potato". If there is an adjective, go by that first letter, for example "a large apple" or "an average potato".
He's another Federalist Society judge picked by Trump. He also blocked a rule that would have extended overtime protections for 4 million government workers in 2024.