For instance, I've heard sanctions defined as "economic penalties imposed for political purposes," or as "Restrictions upon international trade and finance that one country imposes on another for political reasons." These are great definitions for the Aff. Consider that the resolution says that economic sanctions "ought not be used to achieve foreign policy objectives." (And remember that the burden is to prove the resolution true, or false, as a general principle.) This means the Aff can lay a burden on the Neg to prove that foreign policy objectives, as a general rule, justify the use of economic sanctions. Yet I've seen few Negatives that address the overall objectives of foreign policy, other than preventing human rights abuses and nuclear proliferation.
Surely these are not the only objectives of foreign policy; not only is foreign policy a vast entity, but no single nation is implicated! In fact, it might be argued that for most nations, sanctions, for the most part, are a means of keeping their enemies in check. There are no guarantees that political goals are either legal or moral, especially when the Neg cedes to an Aff definition like the one cited above.
It gets worse for the Negative if trade sanctions aren't distinguished from economic sanctions. Then we have a much broader debate about how powerful players keep weaker countries in line. Then sanctions become a tool of economic oppression. (This also makes the free trade argument that much stronger.)
Much better definitions of sanctions, for the Negative, include...
* International Law. action by one or more states toward another state calculated to force it to comply with legal obligations.The first and third make it a legal matter, rather than a political matter; the second makes it a moral matter. Either way, you're at least working to avoid the charge that sanctions are, like war, in Clausewitz's famous formulation, merely "the continuation of politics by other means."
* A penalty, specified or in the form of moral pressure, that acts to ensure compliance or conformity.
* A coercive measure adopted usually by several nations acting together against a nation violating international law.