Presenting the Gospel

A number of commentators have commended Ken Ham for presenting the gospel several times during his debate with Bill Nye. However, a problem with that commendation is that, in the context of a debate over creation science, the credibility of the gospel is tied to Ham's ability to make a credible case for creation science.

I think some commentators are acting as if the gospel is somehow a stand-alone presentation, independent of the context in which it's given. It's easy for me to imagine some listeners saying to themselves, "That's a beautiful story, Mr. Ham. A beautiful fictional story. Pity the Bible isn't believable." 

This is not like a debate over evidence for the Bible, which would, in turn, lay a foundation for a gospel presentation.