The Gish gallop is the tactic of burying an opponent under more claims than can possibly be answered in the time available. Each one may be weak; that is not the point. The point is the count.
It works because refuting a claim takes far longer than making one, so an opponent who answers honestly will run out of clock long before they run out of claims — and will look evasive for the ones they skipped.
A speaker makes fourteen assertions in ninety seconds. Their opponent has two minutes, picks the three weakest, and dismantles them. The audience is left with eleven unanswered points and the impression that most of the case stood.
Named for the creationist Duane Gish, who used the technique in public debates through the 1970s and 80s.
The Gish gallop is best understood as an exploitation of asymmetry rather than a flaw in reasoning. It is sometimes expressed as Brandolini's law: the effort required to refute nonsense is an order of magnitude greater than the effort required to produce it. A debate format with equal speaking time is therefore not a level field, because the two sides are not doing work of equal cost.
This makes it unusually resistant to the normal remedy. Pointing out that an argument is fallacious usually takes a sentence; pointing out that fourteen claims were made in bad faith takes longer than answering one of them would have.
The practical responses are structural. Decline the premise that silence equals concession, and say so explicitly. Answer two or three claims completely rather than all of them partially, and name why: a case that depends on volume rather than strength is one where the strongest example should be enough. Where the format allows, ask which single claim they would stake the argument on.
Online the tactic survives in a modified form, where the galloper posts a wall of links rather than claims. The economics are the same.
