At the very least, I'll give Harper this: his foreign policy position on Israel is quite clear. Unfortunately, the conflict in Israel/Palestine is not black and white, despite what our current leaders want to believe. The Israeli government is not always good, threatened by "evil Palestinians", nor are Palestinian leaders the good guys, threatened by the "evil Zionists". Of course, we are willing to condemn Israel when the US does - though this condemnation is hardly equivalent to the condemnation it heaps upon the Palestinian leadership (and Hamas, though of course this is more justified).
Canada's stand on this conflict should be based in large part on the international consensus, which is generally that a two-state solution is required and should be (largely) based upon the 1967 borders. The problem with blindly supporting Israel is two-fold: 1) You alienate pretty most of the population in the Arab (and Persian) world. 2) Israel will be doomed to continue policies that make it less secure: witness the recent attacks on Lebanon (2006) and Gaza.