All airlines will give you some painfully short connections, and there's no "weighting" done by which a 26 minute connection in one airport would be reasonable (like most cases at DCA) but at another airport would be tough to make (CLT or PHL). There's also the variable of where your gates will be; apart from RJ's and Express Flights that may utilise a consistent set of gates, your connection may be on the other side of the airport and may be on the adjacent gate. Personally I'd love it if more human logic went into building itineraries, so that i'd not have to weed out ones that had a legal connection but still so short that it's worrying, but that's just not how the industry works. So it's on us, as passengers, to know what we're getting into when we book our trips. Yes, airlines do pad their schedules (and the legacies have been accused by WN of padding too heavily, to make their numbers look good) but the OP is right, all it takes is 3 or 4 minutes to go from a close call to a missed flight.

While I feel the ultimate responsibility is with the OP-- honestly, many folks would feel uncomfortable with such a short connection in such a busy airport and all the variables like ATC and weather thrown in--- I do feel US should cover any reasonable out-of-pocket costs; the OP booked a legal connection, wasn't gaming the system, and did his/her part to get to the second flight but still didn't make it, so if there's a hotel expense or meals, US should cover that, following of course the normal compensation guidelines (no steak dinner compensation or penthouse suites). But nothing due for time missed from family as that is a risk every one of us takes, every time we fly. A token amount of miles as a goodwill gesture is probably in order. But in all honesty, the OP is the one responsible for choosing the itinerary and might not have had these challenges if he/she had booked an alternate flight.