We often say we need to debate something - especially in the political world - when what we really need is a dialogue.
Dialogue is collaborative: two or more sides work together toward a common understanding while debate is oppositional: two sides oppose each other and attempt to prove each other wrong.
In dialogue, finding common ground is the goal while in debate, winning is the goal.
In dialogue, one listens to the other side(s) in order to understand, find meaning and find agreement while in debate, one listens to the other side in order to find flaws and to counter its arguments.
Dialogue enlarges and possibly changes a participants point of view while debate affirms a participant's own point of view.
To resolve issues and make decisions, we need both debate and dialogue. One is not intrinsically better then the other - they serve different purposes. But we have a strong tendency to enter into debate and even argument when we should be doing is having a dialogue.
