neighbors dog is threatening and loose

[littleindiangirl]

most laws state dog must be under control within city limits.

I think your wrong there, you may have meant to say, most counties, or perhaps most cities... but not most states, as only Michigan and Pennsylvania have leash laws blanketing the entire state.
Only about 10 states have laws in regards to loose dogs, and they do not all require a leash

http://www.animallaw.info/articles/ovusdogleashlaws.htm