THE ISSUE: A comprehensive immigration plan that includes a guest-worker program. ("Base Desires," Dick Morris, PostOpinion, June 26). **** No one with any common sense believes the Senate immigration bill would really be enforced. Rather, it would only begin another round of illegal entries into the country. Bloomfield, Conn. **** Grass-roots conservatives, who worked hard to get President Bush re-elected........will not support a plan that includes amnesty. Lyles, Tenn. **** The resultant population drain and strain on our social programs will surely reduce the United States to just another Euro-type weakling.........enforce existing laws that heavily fine employers of illegal immigrants....