Before the government began the drug traffic did early gangs also serve as neighborhood watch?

Neighborhood watch. Hmm. Isn't that kinda like protection insurance? For a fee, they won't beat the crap out of you.

No I don't buy into any of that. Seems like you have been watching to much TV.  Gangs used the drugs to increase their power. 

That depends on what you define as a "gang".
There have always been criminal gangs ... and the only "neighborhood watch" they were, was to keep competing criminals out of their territory and extort money from innocent people.

There have also been early "gangs" that WERE organized "neighborhood watch", operating either within the law or in conjunction to it.

Then there were vigilante "gangs" that claimed to be doing the work of the law, but many times were just using the law to further their own power.

Ya they watched that no one else was selling drugs on their turf. cheers!