Pollster John Zogby is helping us again, this time on determining if possible late entrants into the presidential race like Republican Newt Gingrich or Democrat Al Gore can really wait until September or later to jump in. His view: You betcha. "Gingrich can wait until the fall," Zogby says, "particularly if the major candidates prove tiresome or flag in some way." Or, he adds, if "Republicans decide the election is hopeless and they might as well go down in a blaze of glory." Gore "can and must wait because right now 75 percent to 80 percent of the Democratic early primary and caucus voters are satisfied with the field," he says. Gore's signal: when the front-runners slump "or screw up."