Denver (CNN) -- To win in November, Mitt Romney must emerge from his first debate with President Barack Obama as the leader on this campaign's defining question: Which candidate do voters trust more to handle the economy? "He has to paint a compelling picture of a better economic future and why he can lead us there and President Obama can't," GOP pollster Whit Ayres told CNN when asked to define Romney's paramount debate challenge. Democratic pollster Peter Hart made the same point but in more colorful language: "If Romney loses this issue, then he is toast." How to watch, clip and share the debate
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Campaign's defining question is who voters trust to handle economy
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Romney faces same question all challengers do -- is he credible alternative?
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Obama faces challenge of showing how next four years would be different from last four
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Bottom line is the debate rests on which of two men on stage are more persuasive
Yes, there are other important challenges for both the Republican challenger and the @placeholder incumbent as they share the debate stage for the first of three encounters.