Key dates showing whether major crime declines were already underway before federal or National Guard interventions.
| City | Evidence Before Intervention | Federal Action | Guard / Surge Timing | What Timing Establishes |
|---|---|---|---|---|
| Washington, D.C. | Homicides were already down 12% YTD through Aug. 6, 2025 vs. 2024. | Crime-emergency intervention began in August 2025. | Federal surge period in MPD report begins Aug. 7; Guard deployment announced Aug. 11. | The decline predated the intervention, though homicide fell further during the surge. |
| Memphis | MPD announced 25-year lows across major categories on Sept. 9, 2025. | Trump memorandum signed Sept. 15; task force began week of Sept. 29. | Tennessee National Guard patrols began Oct. 10, 2025. | The Guard cannot have caused the large decline already documented before Oct. 10. |
| Los Angeles | Not used here as a clean crime-treatment case. | June 7, 2025 memorandum responded to immigration-enforcement protests. | Guard mission centered on protection of federal personnel/functions/property. | L.A. is a weaker test of a citywide anti-violent-crime strategy because that was not the deployment's original stated mission. |
Timing can disprove claims that an intervention caused changes that occurred before it began, but timing alone cannot establish whether the intervention produced an additional later effect.