Is Bush really christian?

Or does he just use his "christianity" to score political points? I always guessed that, but now we seem to have a confirm.

More than five years after President Bush created the Office of Faith-Based Initiatives, [David Kuo] the former second-in-command of that office is going public with an insider’s tell-all account that portrays an office used almost exclusively to win political points with both evangelical Christians and traditionally Democratic minorities.

I guess the same can be said about Berlusconi, devoted (and divorced) catholic... or almost any other politician, real or fictitious (The Saldana dinasty from Hamilton's Confederation books comes to my mind...)