I think most liberal Christians are confronted with the question, if the 'historical Jesus' was not accurately depicted in the New Testament, and that this individual - whomever he was in real life - was not the identical individual spoken of in the New Testament, then what basis has the Christian faith in worshipping this man called Jesus of Nazareth?
That's a tough question, and one that many liberal Christians are apt to answer in a myriad of ways. My answer to this issue is first to acknowledge that the historical Jesus, if we could somehow trace his existence down to a science, would not be Jesus as spoken of in the Gospels. This is not to say that he wasn't a religious leader, or he didn't interest the masses as a Messiah, etc, rather its only to say that the Christian faith evolved, and as it evolved, it began to attribute more and more to Jesus than what was actually present or said by the Jewish man who lived somewhere around 2 millenia ago.
My second response is to say, for other than historical purposes, we can forget about the historical individual named Jesus. What I mean by that is that the historical individual is not important for the religious identity that Jesus is for the Christian community, and it is afterall, the Christian image of Jesus that Christians worship and for good cause. To remove the things said and described about the Jesus of the Bible is to reduce the Savior to the point to where the Christian faith would be greatly diminished, and perhaps nothing more than a slight respectful image of him - but, nothing of a Messiah or Savior image.
This answer, of course, begs the question. How can an image or a depiction of a historical person other than what he is, be anything of value or have any Savior image that couldn't also be said of Superman, or Spider Man, or Batman, or any other fictional character?
The answer, I think, is that the basis for those fictional characters were entirely imaginary, whereas the basis for Jesus the Savior is based on a real person, a person tightly tucked away in the mysteries of history, and of which we can only speculate and probably never know.
The important issue for modern Christians, I think, is that the early Christians had no problem attributing more supernatural characterizations to the historical Jesus because this is what they perceived of the real person. As the time of his death moved further and further away, the legends grew, and putting those legends into an orthodox perspective also became apparent. The need for the Gospels was imperative. The Gospels were a compliation of all the things about the historical Jesus that seemed real, or could be recollected from memory through the first and second generations that came into contact with the man or his associates. Hence, the Gospels were born.
This, in my view, means that whoever the historical Jesus was, he was akin to the miracles, the might deeds, the fabulous sayings and wisdom uttered by Jesus in the Gospels. Some of which he might have said, much of which he probably didn't say - but inspired in other individuals to eventually to say and write.
I'm reminded of the movie a few years ago called 'Unbreakable'. As a movie, it was so so, but what was remarkable about the movie is that it took a comic book superhero and a supervillian, and made them ordinary, like us. However, they were not just like us, they were the inspiration for their superhero and supervillian images that a comic book could exaggerate and make into the fictional characters of supernatural type abilities.
What interested me in this movie is that the real characters behind the superhero and supervillians were actually more powerful and amazing than the comic book version. No, they didn't have all the super human abilities, but they had the inner core of why you could imagine a super human ability could be attributed to them with a little imagination.
In fact, without the comic book image, the things you would say about their 'historical' characters just wouldn't do justice to accurately describing them in a manner that would elicit any kind of amazement. This amazement can only be communicated by the process of attributing super human abilities, and that's how we can easily recognize them for the both super hero and super villian that they were in real life.
So, I think, it is with Jesus. We may never know the historical Jesus. We may never know what miracles happened, which happened but more in a naturalistic way, and which were attributed to Jesus for other reasons (e.g., people didn't respect the real story of what happened because it didn't have the magnificence that the actual experience conveyed, so some miracles were attributed so that the magnificence of Jesus was communicated). However, what we do capture from the New Testament is one very important factual portrayal of Jesus: how extraordinary he was and the attention he garnered in his ministry.
So, the question: "if the 'historical Jesus' was not accurately depicted in the New Testament, and that this individual - whomever he was in real life - was not the identical individual spoken of in the New Testament, then what basis has the Christian faith in worshipping this man called Jesus of Nazareth?" Can be answered like this, the basis for Christian faith in worshipping this man whom the Gospels might not accurately portray is that this portrayal is what is needed to accurately portray the importance and magnificence of this human being who lived 2 millenia. What we worship as Christians is not the miracles and not the great sayings, but his place in human history as that voice that awakened humanity to something bigger and something more profound. This is what makes Jesus the Messiah and his profound gestures and willingness to sacrifice himself is what makes him the Savior. Maybe that's why his followers couldn't let go.