This study analyzes the rhetorical strategies employed by candidates, Barack Obama and John McCain, in the third presidential debate of 2008. Particular attention is given to candidates’ use of acclaims, attacks and defenses, as defined by functional theory. The analysis also recognizes the presence and important role of candidates’ “nonfunctional” statements and overlapping function units, two linguistic occurrences unexplored in previous studies. This research confirms the value of functional theory for investigating interaction in the context of political debate and also points to the need to include other aspects of linguistic theory in future investigations.