Rebuttals are what make debate debate. Rebuttals are the fire of the debate, where the passion comes out in a team. Rebuttals are what require logic, quick thinking, and what truly exemplify a great debater.
Why are they so important?
Rebuttals are, in a nutshell, the single most important thing in a debate. Sure, you could have a billion points to support your side, but so could your opponents. How does a judge distinguish between four points that look the same, feel the same, and are the same except for the fact that they're on two different teams? Rebuttals.
What is it?
A rebuttal is a refutation to an opponent's argument. What that means is that you contradict what your opponent says in a way that makes their points null and void. And, if they don't have any points standing, then they lose the debate by default. So, rebuttals, also known as "refutations", are key to an intelligent debate.
How to rebut.
Now, how does one rebut, then? Well, there are a multitude of ways to do it, and it's not a one-size-fits-all-assertions kind of thing. Rebuttals can be carried out with evidence. Evidence or a statistic that contradicts what your opponent's said. Maybe outweigh their source with two sources. Or with a more reputable source. The choices are endless.
Or, maybe you could try to use a logic rebuttal. These are rebuttals that use logic, common sense, and reasoning to refute an opponent's point. These are the most foolproof types of rebuttals, for your opponents can't try to disregard logic. These rebuttals can be based on something dumb or contradictory your opponents said in a POI you asked one of their speakers. Or maybe your opponent's point just made too big of a leap that couldn't be possible. Or maybe their point disregarded the negative side effects that have to occur to make their argument work. Or maybe even their point ignored what would actually happen in the real world if their plan was implemented and instead they just thought about one pathway and not the myriad of other bad ones their plan could go down. As you can see, there are many ways to refute an opponent's point with just pure, simple logic without the need for evidence or sources.
You may already know this, but the only speaker that doesn't get a chance to rebut is the 1st proposition speaker. Other than that, every single speaker has the opportunity and should take advantage of this opportunity to try to rebut their opponent's points. Just remember that rebuttals are what make a debate a debate, and you'll be fine.