A stop-cut, in sabre fencing, generally consists of striking with the edge of your blade the weapon-arm of your opponent as he is in the process of making an attack--or, more properly these days as I understand it, the stop-cut is made as the attack develops, but before the attack has been established.
Sabre like foil is subject to the rule of right-of-way. An attack will always win a point if it is not first parried. So, if I fencer is being attacked, the attacker has the right-of-way and, even if the attacked fencer strikes first, the attacker scores, unless the attack has been appropriately parried (blocked) by the blade of the fencer subject to the attack.
Especially as speed is emphasized in sabre today more than it ever has been, it is difficult to make an effective stop-cut. It is particularly difficult for the older, slower, less agile fencer (that would include me, alas). I have made what I thought were perfectly nice stop-cuts only to find the point going to my opponent. An attack, it seems, develops very swiftly indeed these days. I wonder if the emphasis on speed and the attack is good for the sport. The art of defense, and therefore skill, in fencing is diminished where speed takes precedence.
There is a parellel with the art (should I say sport?) of disputation. Particularly since the arena of argument has become so all-encompassing, and so dominated by media which regularly relies on instant analysis, and also because, I think, of a reduction in attention span arising from the speed with which words and thoughts are exchanged, an attack in argument will most likely "win" in the sense that it will be remembered, and recognized, more easily and clearly than any rebuttal. An attack in fencing or in argument can be made with skill, certainly. But, an effective defense will generally require more skill, and moving from a defense to a counter attack is an ever greater test of the skill of a fencer or debater.
The result is not merely that the use of skill, and therefore intelligence, in debate of issues great or small is decreased. Attacks, though successful, are as a result less and less subject to test, and we have less and less chance to determine what argument would win out in a true test of ideas.