Dan, my friend, I voted for Springfield, but what I wanted to suggest to you is any top-quality (e. g., Kimber, Springfield, and – perhaps, once again – Colt) 1911A1 chambered in .45 ACP. My rationale follows:
a) As much as like the Sig “P seriesâ€, the CZ 75/85/97 and even the H&K USPs, I believe SIMPLICITY is the key to both safety and effectiveness. This is particularly true since, as you stated earlier in this thread, most law enforcement officers are NOT “firearms people†and constant practice is most unlikely. Therefore, one should strive for a single, straightforward, unambiguous, and invariable “manual of armsâ€. To me, this means no DA/SA autoloaders; rather, SA only.
b) Further, while I prefer SA for safety, a positive mechanical safety is CRUCIAL – once again, especially due to officer firearms non-interest and marginal proficiency (i. e., no Glocks). As you know well, 1911A1s have a series of safeties, specifically including the “positive, mechanical†thumb safety. In my opinion, a well-maintained and top-quality 1911A1 is extremely safe in Condition One, since – unlike a Sig or a Glock, among others – it cannot be fired without the affirmative action of disengaging the mechanical thumb safety (no “trigger pull†ONLY, however long or short, for the first round is possible).
Beyond safety alone (and I realize this is the focus of your inquiry), the .45 ACP is a proven, potent “stopperâ€. Add to this the possibility of 10+1 carriage (Wilson KZ-45, for example) plus 200 grain +P JHP loads – with increased muzzle velocity to ensure both penetration and expansion – and (IMHO) you have an outstanding LEO handgun: VERY safe, effective, trainable, reliable, durable, maintainable, and accurate.
With every best wish -- Roy