This word is used too much, but in Buchanan's case it's actually the correct label. Buchanan is literally a fascist, or at least he was back during the 90s when he was relevant. He's probably moderated a bit since then, but he still seems to retain a lot of his old views and is just more tactful about expressing them.
I agree, and I don't use the term often. I genuinely believe that Pat Buchanan is a fascist in his positions and his Nazi apologism and on record anti-semitism don't help him in that department, either.