ORD, summer, connecting from domestic to a once-a-day longhaul international flight, one hour connection.

IMO, dicey. I'd pay CFC fee and go earlier, and feel much more at ease.

Yes, I've made lot of ORD connections - and missed a number of them, having AA reaccommodate me on other airlines. Sometimes it was groudn holds because ORD was controlling slots, sometimes because of weather and extended in-air holds giving us nice "racetrack" views of the area north of ORD, etc. A bit of a PITA at the best of times.