Such as: Before the assassination attempt, Biden had proclaimed that people needed to put Trump in their sights.
The Secret Service had asked for personnel but were turned down.
RFK, Jr., Biden's main opposition in the primaries, whose father and uncle were both assassinated, was denied ANY Secret Service protection at all.
A congressman introduced a bill to deny Trump any Secret Service protection at all.
Jill Biden had an event the same day in Pennsylvania that pulled Secret Service personnel from the pool of available talent.
Trump's SS detail seemed to get at least some of the "B Team", the Ponytail Brigade:
https://www.thegatewaypundit.com/2024/07/ponytail-brigade-utter-humiliation-gaggle-female-secret-service/
The shooter was spotted by onlookers as he climbed the building and onto the roof with his rifle in plain view:
The shooter was spotted by law enforcement nearly 30 minutes before shots fired, and reported it to authorities at that time:
https://www.wpxi.com/news/local/alleged-trump-shooter-spotted-by-law-enforcement-nearly-30-minutes-before-shots-fired-sources-say/Q6GIK5RP6RBY5PHIMYBNXRTEBI/
The SS Sniper apparently had the assassin in his scope crosshairs for some time, but did nothing. He raised his head after a while and then the assassin fired, at which point he put his eye back on the scope and shot the assassin.
https://nypost.com/2024/07/13/us-news/video-shows-moment-secret-service-snipers-kill-trump-gunman/