Kant, generally, opposes violent revolution. As he writes in the first appendix to "Perpetual Peace,"
If a violent revolution, engendered by a bad constitution, introduces by illegal means a more legal constitution, to lead the people back to the earlier constitution would not be permitted; but, while the revolution lasted, each person who openly or covertly shared in it would have justly incurred the punishment due to those who rebel.Thus, the Neg can use Kant to establish several burdens that the Aff must take up in order to justify violent revolution.
The Aff would have to show that political oppression--defined carefully, of course--somehow forces citizens to choose between following written laws and the categorical imperative. In the article "Is Revolution Morally Revolting?" Ryan W. Davis writes,
The problem is that unjust states frequently impose laws not only restricting behavior but also prescribing actions Kant would reject as immoral. In such cases, revolution could be justified.A second burden exists. Again, Davis:
Kant believed that a social contract was a moral as opposed to prudential necessity; without it, no community of moral agents would exist in which autonomous self-legislation could occur, thus posing an immediate threat to the moral order. Hence, one of the criteria for a justified revolution might be the preservation of at least some social contract. Revolutionaries would have the burden to ensure that once they disavowed connection to a prior state, they would have a previously crafted replacement already prepared for implementation. In this way, revolutions that immediately established new contractual orders, such as the American or even conceivably the French Revolution, could be justified while random acts of state subversion could be expurgated.Affirmatives might do well to consider whether political oppression generally qualifies as a violation of Kantian maxims.
Also, advocates of either side would do well to consider Paul Guyer's take on the subject:
On the other hand, Kant accompanied these liberal doctrines with a denial of any right to violent revolution, which has seemed surprising to many. But Kant's thought here is complex. Underlying his position as a whole is his view that in any situation in which different persons are bound to come into contact with each other we have not merely a moral right but a moral obligation to found or uphold a state. But one could easily argue that a tyranny is a state in name only, and that our moral obligation with regard to a tyranny is precisely to replace it at any cost with a legitimate state. Kant offers several reasons why this is not so. One claim is that violent revolution does not leave time for genuine reform in principles (8: 36), and another argument is that people revolt for the sake of greater happiness, which is an illegitimate reason for the overthrow of a state (8: 298). But these are empirical claims, and do not prove that people cannot revolt solely to remove illegitimate constraints to their freedom. Another argument Kant makes is that a constitution granting a legal right to rebel against the highest authority it creates would thereby not create a single highest authority after all, and would thus be self-contradictory (6: 319 ). This has seemed to many to be a sophism; but it may have been Kant's attempt to get his liberalism past the Prussian censorship, denying a legal right to rebel without ever explicitly denying a moral right to rebel.So, an Aff may not be completely bound by Kantian strictures.