evidence: U.S. Secret Service Director Kimberly Cheatle, facing deepening scrutiny over an assassination attempt against former president Donald Trump, took responsibility Monday for her agency’s failure to prevent the attack but said she would not resign. [...] The Secret Service agents who protected Trump and killed his attacker have been widely praised for acting quickly and decisively. But it remains unclear how Crooks was able to gain access to a nearby roof with an AR-style rifle. [...] Emilio T. Gonzalez, a former Army intelligence officer and Homeland Security official, said the shooting revealed flagrant flaws in the Secret Service’s planning and resources. He said he thought much of Trump’s security detail should be replaced since the shooting.