Many newspapers limit the frequency an individual writer can appear in their letters columns. You should consider adopting such guidelines.
Perhaps you could start by limiting Tony Smith - either that or put him on staff, heaven forbid. Erase the heaven forbid. I don't want to inject my Christian Taliban opinions.
If you won't limit him or put him on staff, perhaps you could save space by just printing the Internet address of the site where he gets his talking points.
Note: this is not a personal attack on Mr. Smith. I have no problems with him as a person - just how often his rantings appear on your pages.