“If you don’t mind me saying so, you seem young to be a professor.”

“I’m thirty-five. Besides, I was only an associate professor when I left Princeton. That’s a little like saying you’re a company vice-president.”

“Thirty-five, I guess that’s not so young. Not these days. In the army they’d think you were an old man. They’re only boys, most of them. Sometimes it just breaks my heart to think how young our soldiers are.” He raised his glass in a silent toast.

I returned it, then sipped the martini. It had way too much gin for my taste, and it was not too cold if you like drinking liquid hydrogen. Still, it wasn’t every day the president of the United States mixed you a cocktail, and so I drank it with a proper show of pleasure.

While we drank, I took note of the small things about Roosevelt’s appearance that only this kind of proximity could have revealed: the pince-nez that I had always mistaken for spectacles; the man’s smallish ears-or maybe his head was just too big; the missing tooth on the lower jaw; the way the metal braces on his legs had been painted black to blend in with his trousers; the black shoes that looked poignantly unworn on their leather soles; the bow tie and the worn smoking jacket with leather patches on the elbows; and the gas mask that hung off the side of the wheelchair. I noticed a little black Scotch terrier lying in front of the fire and looking more like a small rug. The president watched me slowly sip the liquid hydrogen, and I saw a faint smile pull at the corners of his mouth.

“So you’re a philosopher,” he said. “I can’t say I know very much about philosophy.”

“The traditional disputes of philosophers are, for the most part, as unwarranted as they are unfruitful.” It sounded pompous, but then, that goes with the territory.