The shift to the middle could alter the gun debate this year. In 2000, candidate Bush attacked Gore for failing to enforce gun laws already on the books. Now the Dems in the survey hammer Bush for what they say is his own lousy enforcement record. Though both sides might prefer to sidestep the volatile issue, that could be tough. There are four major pieces of gun legislation on deck in Congress–including the assault-weapons ban and a proposal to grant gun makers and dealers immunity from lawsuits.