I see the Israelis as being ultimately an ally, but there are things about their relationship with the US that I do not approve of. They do conduct espionage against us, and they do turn around and sell our technology to countries like China. To a certain extent it's to be expected that governments, even friendly ones, snoop on each other. But there's a force among conservatism that treats anything pertaining to Israel sort of like they do with the police, i.e. don't you dare criticize anything they do.
Jason Lewis speaks of this often. He takes it too far, in my view, by treading dangerously close to moral relativism in regard to the Israeli/Palestinian conflict. But his view on foreign policy in regards to Israel has become one of America distancing itself from the internal conflicts of others, Israel included.
Even though I believe that Israel is among the most natural and necessary US allies, I think there are a few forces at work that cause conservatives to look at Israel with glasses sometimes more rose-colored than warranted.
In the view of most conservatives, America is a Christian nation, or at the very least, we recognize the fact that America was founded on Judeo-Christian principles. Israel is a Jewish nation in much the same way the US is a Christian nation - secular government, inclusive of other religions or the non-religious.
However, regardless of the form of israel's current government, the nation of Israel being equated with Judaism is a biblical fact. The Hebrew people are God's chosen. Jesus Christ was a Jew. Therefore I think that many American Christians are uncomfortable separating the Jewish people from the deeds of the state of Israel, even though many Israelis are secular Jews, and the actions of the nation are not necessarily sanctioned by God.
Also, conservatives remember history. We understand and acknowledge the Holocaust. It is the Leftist ideology that condones exterminating undesireables in their drive for ideological domination. It is the Leftist ideology that always devolves into anti-semitism. We recognize and abhor that.
Finally, we understand the difference between good and evil. We recognize the evil of Islam, and naturally understand that our friends are those who ally with us against it. In that regard, there is no better friend than Israel.