I sent Mr. Yost to REI for a solution. He returned with a bottle of Nikwax TX.Direct Wash-In. The bottle cost around $10 and can be used on 3 garments. I figured if it worked, it was worth the $3.
I need to disclose that we couldn't find any directions on the bottle. It didn't say anywhere how much to use, how to use it, etc. We looked on the company's website only to have it say, "see the bottle for directions." Finally, a Google search led me to peel away the sticker label on the back to reveal the information. It was a little irritating that there wasn't "peel here" or something like that. Nevertheless, we were now ready to give it a try.
We did a "before" test by dropping some water onto the backside of the snow pants. You can see that the first initial drops did bead up, but within a few seconds, they'd soaked in.
We ran them in our front-load washer with two caps full of the product, dried them on low, then tested them again.
This picture is right after I dropped the water. My trusted assistant was out wrangling kids during the "after" test, so I don't have the exact same picture as above. You can see that virtually all of the water is beading up.
*The pants look like they are a different color than before, but I think it is just the difference in light from morning to afternoon.