The version that works as a tactic tends to add one thing: the weakened argument is more objectionable than the real one, so answering it costs you something even when you win.
Why it works
Refuting the real argument is hard. Refuting a version of it that nobody holds is easy, and a reader arriving late has no way to tell which one was on offer — they see a position, and they see it demolished.
It also transfers the burden. You now have to establish what you actually said before you can return to arguing for it, and that is unglamorous work performed in front of an audience that has already heard the exciting version.
What it looks like
- "So what you're saying is…" followed by something you did not say
- A qualified claim restated without its qualifications
- An example you gave treated as the whole of your position
- The most extreme reading of an ambiguous sentence, presented as the obvious one
- Your argument merged with a worse argument made by someone else
The honest difficulty
This is an easy label to reach for too quickly, and worth being careful with.
Sometimes a restatement that feels unfair is simply an accurate reading you did not intend. Sometimes an implication you did not notice really does follow. And "that's a straw man" is itself a convenient way to avoid an uncomfortable but faithful summary of your view.
One thing worth trying is simply offering the accurate version and seeing what happens to it. It is not decisive — someone can defend a genuine misreading stubbornly — but a correction that is ignored rather than engaged with tells you something about what the exchange is for.
What to do
Restate, don't complain. "What I said was X" is stronger than "that's a straw man", because it puts the real claim back in front of the audience instead of starting a dispute about labels.
Do it once. If the corrected version is ignored and the weakened one comes back unchanged, you have learned what you are going to learn from this exchange. That is not a verdict on the other person's intent, which you cannot see — it is a fact about how much further the conversation is likely to get.
Notice who it is addressed to. A version that comes back unchanged after correction is not really being said to you, since you have already answered it. Whatever you say next is for the people reading, and should be short.