A counterplan is an alternate plan run by the Negative. It argues that the Affirmative plan prevents the enaction of a better plan (the counterplan), so the judge should vote against it. Counterplans are not extremely common in the NCFCA and Stoa, but do appear regularly.
While there is dispute over the precise limits and abilities of counterplans (see below), it is almost universally accepted that a counterplan must "compete" with the Affirmative directly: that is, it must provide a reason why the Affirmative is bad, not just another nice option. This is most often accomplished through mutual exclusivity, where the counterplan and the Affirmative plan simply cannot be enacted at the same time (as with "abolish nuclear weapons" and "deploy nuclear weapons to Panama"), but it can also be accomplished in more subtle ways. For example, enacting both the counterplan and the Affirmative plan at the same time might trigger a unique disadvantage, which enacting the counterplan by itself would avoid. (Main article: Competition)
Negative fiat: There is some dispute over whether the Negative has fiat power to pass their counterplan in the first place. The majority of debaters in the NCFCA and Stoa accept Negative fiat, but some have raised theoretical objections to it (generally concerning its fairness and extent.)
Topical counterplans: Whether or not topical counterplans are a legitimate Negative argument is one of the most controversial theory topics in the NCFCA and Stoa. This question is primarily responsible for the ongoing popularity of nontraditional resolutional interpretations, such as plancentrism and (more commonly) parametrics.
States counterplans: One particularly common counterplan, in which the Negative adopts the Affirmative's plan using the 50 individual state legislatures instead of the Federal government, is highly controversial. Some hold that it is an abuse of Negative fiat, while others disagree and believe that federal vs. state implementation is a worthwhile issue to discuss.