Atlas V had a partial failure in 2007, cutting down the operational life of the satellites. The most recent Cyngus mission was also nearly a failure when MECO

Atlas V had a partial failure in 2007, cutting down the operational life of the satellites. The most recent Cyngus mission was also nearly a failure when MECO occurred 5 seconds prematurely, but Centaur was able to make up the difference. Atlas I and II also had a healthy number of failures, so the question is whether you consider III and beyond a new vehicle, or a continuation of a single development program. CRS-7 was certainly a blow to SpaceX. There's no sugar-coating that, but there's no such thing as certainty in space. Even with the stellar Atlas V record, there's still risk. Also, for this mission, no justification needed to be made, as ULA did not submit a bid. And yes, Falcon 9 went through a lengthy certification process.