It’s not too much to ask police officers to obtain warrants and to knock and announce their presence in all but the most exigent circumstances. In both Scott and Mendez, there was no good reason for police not to identify themselves. Yet in both cases, a resident’s reasonable response to police failures undermined his efforts to hold them accountable for those failures in court. That is unacceptable. When a person enters my house unannounced, I should have the right to hold a gun in my hand. To argue otherwise is to eviscerate the Second Amendment.