Beginning

• I am here to argue for / against the motion…
• I would like to put the argument for the affirmative side of the motion…
• We are here to argue the motion…and I intend to argue against it.

Introducing your position

• The reason I believe that [smoking should be banned] is simple. 
• Let me begin by saying…
• Allow me to outline my argument…
• If you will indulge me, I’d like to tell you about…

Refuting the opposite view

• Our opponents would have use believe x, but they are mistaken.
• It might seem logical to accept the opposing argument, but in fact it is deeply flawed
• My opponents might argue that … , but such reasoning is faulty. 

Giving reasons

• The reason I think this is…
• The evidence clearly suggests that…
• One of the reasons I’m convinced of this is…
• There can be no clearer evidence of this than…
• There is ample evidence to suggest why this is the case. 

Conclusion

• I hope that I have demonstrated…
• I’d like to leave you with the thought that…
• I trust that you will agree with me that…