SS did not “muff” it, they did their part.
Trump was spared by the Grace of God.
“The former president was a few minutes into his remarks at a campaign rally in Butler, Pennsylvania, when he suddenly turned his head to the right to view the chart that was displayed on a screen next to the stage. It was at that moment that the would-be assassin, identified by the FBI as Thomas Crooks, shot towards the former president and into the crowd, clipping Mr. Trump’s right ear.”
https://www.fairus.org/news/executive/immigration-chart-changed-history