Right, but the directional trends on murder is going well - in other words, dropping in the US and increasing in Europe. Esp. Britain. We're still "ahead" of them for now, but that won't last at current trends.
Now...the reality is, the murder rate in the US is driven largely by prohibition (err, the "War On (Some) Drugs"[tm]). End THAT and whoa...it'll be interesting about five to ten years later.
When the earlier prohibition ended there was a brief spike in violent crime as a small chunk of the rum-runners turned to bank robbery and kidnapping. Didn't last though.