Always keep your villagers near coin mines safe, or they will get killed. Towers work best, but won't stand up to an actual army, only raids. Walls won't work against ranged units (at least not skirms, if the wall is big enough). Still, I tend to go for every coin mine on the map within reason before building the expensive plantations.
"Republicans who did not play the patronage game were ridiculed as the Mugwumps for sitting on the fence--their "mugs" on one side of the fence and "wumps" on the other. Historians generally consider this era a low point in American politics."--United States History by John J. Newman and John M. Schmalbach