Exactly this. But I would also assign a rebuttal (could be brief), and even the counter-argument to the rebuttal. Get comfortable with the process of reasoning and laying out an argument. Logical reasoning shouldn't stop because your agenda is satisfied. After all, empathy and an understand your opposing view's perspective should help you refine your case, or even your position if you have an open mind.

We recently did one of these with my son on fracking. While the initial stance was "not worth the risks," there were several compelling counter arguments, especially when taking second order effects into account. It's clearly not a cut and dry issue, but one that depends heavily on context.