Question about Messianic Jews

My understanding of a Messianic Jew is that they believe that Jesus is the son of God.
Isn't that the definition of a Christian?

In fact, it is the one true thing that distinguishes Judaism and Christianity. The "have your cake and eat it to" approach of the Jews for Jesus (the name that has largely been dropped because it rightly sounded too cultish - which is in many ways how the Jews for Jesus operate - has been designed to appeal to the guilt instinct in many. You can retain your Jewishness without actually having to remain Jewish. The promotion of being able to remain Jewish has been the core of the prosletyzing message of the Jews for Jesus. I have a lot more respect for those who are honest and simply identify what is happening as a conversion to Christianity. If someone wants to convert to Christianity, go for it. But the church that is accepting the convert should be honest about what is happening.

are Christians by faith, but maintain Jewish traditions in their worship

judaism is not a religion whose membership criterion is based on faith, whereas christianity is. by which i mean, whether or not you are considered a jew does not depend on maintaining a particular belief.

consequently, it's possible to be a jew (by your mother being jewish, by identifying yourself as a jew, by keeping kosher, etc.) and also to be a christian (by believing in jesus as god).

I never thought of it in those terms. I was only thinking about it in terms of just religion. I did not consider the ethnicity issues. Thanks again for your input.