Happiness shouldn't be pursued. The pro side of this could start with the obvious pain that people face when their expectations are not met. Maybe it is better to just relax and stop thinking about happiness. On the other hand, the fact that the pursuit of happiness sometimes leads to pain doesn't mean it is without success too. What better thing is there to pursue?
Political Debate Topics
Taxation for non-essential programs is stealing. The pro side can start with the idea that a consensus or majority makes it different, and morally acceptable. The con side can point out that it's wrong to forcibly take your neighbors money to pay for an art program you like, and voting with others to have the government do it for you is no different morally.
It is morally okay to break laws you don't agree with. The pro side might say that there have historically been many bad laws, and that it is almost a duty to break them. We wouldn't want someone to have turned in escaped slaves just to comply with the law. The other side could argue that personally choosing to break the law is corrosive to general respect for laws, and this respect is necessary to a civil society.
Government should get out of the marriage business. If the government had nothing to do with marriage, we could drop all the divisive issues about gay marriage, and just let people marry in whichever churches or other institutions will marry them. Taxing all individuals the same is fairer too. On the other hand, marriage is a long-standing institution, and it would be chaotic to remove the legal element of it. Insurance policies, property title and other legal contracts would all need to be re-written.
Other Debate Topics
We should abolish corporations. It is clear that the legal entity is often used to reduce liability for true crimes. Why not let people own companies directly and own up to their actions? On the other hand, one could argue that the corporations made our economy as strong as it is, and it would be extremely dangerous to eliminate them.
There is nothing morally wrong with doing drugs. Clearly the laws about which plant and other substances you can ingest are arbitrary. There is no reason why it would be moral to have a beer, but somehow wrong to have a joint. On the other hand... (you're on your own on this one).
Intelligence testing is without value. Many people of low intelligence have succeeded in many areas of life. In fact, the most intelligent people routinely fail in business. There is not really anything to be gained by assigning a number to a persons thinking. Of course, whether or not a person succeeds or fails, more intelligence means more potential to succeed in many areas, so it is a useful thing to measure. Whether you can really measure it, and how you define it are just some of the many related debate topics.