A lively debate before an appreciative audience for such things, the place where WFB first won his spurs, the Yale Political Union. Samples: Mr. Shrum: "All of us agree that Mr. Reagan's re-election is likely to mean more for guns and less for human needs, that it is likely to mean escalation and not negotiation in Central America, that it will probably mean a continuing arms race with the Soviet Union. The difference is that while Mr. Buckley and Mr. Will welcome that result, Senator McGovern and I and most Democrats resist it." ... Mr. Will: "It is a sobering thought that if any of the Democratic candidates now running for President had been President in the fall of 1983, an extraordinary band of cutthroats would now be screwing down the lid of a dictatorship on a now free island [Grenada] in the eastern Caribbean."