Harper told an audience Monday that while Israel is receptive to fair criticism, Canada is obligated to stand up for its ally when it comes under attack from others.
"Not just because it is the right thing to do, but because history shows us, and the ideology of the anti-Israel mob tell us all too well, that those who threaten the existence of the Jewish people are in the longer term a threat to all of us."
The prime minister acknowledged that his position is not popular with all governments and organizations, including members of the United Nations and the Francophonie.
"And I know, by the way, because I have the bruises to show for it, that whether it is at the United Nations or any other international forum, the easiest thing to do is simply to just get along and go along with this anti-Israel rhetoric, to pretend it is just about being even-handed, and to excuse oneself with the label of honest broker.
"There are, after all, a lot more votes—a lot more—in being anti-Israeli than in taking a stand. But as long as I am prime minister, whether it is at the United Nations, the Francophonie or anywhere else, Canada will take that stand, whatever the cost."
The prime minister's use of the phrase "honest broker" is an apparent reference to a recent speech made by Liberal Leader Michael Ignatieff.
Ignatieff criticized the Harper government for using Israel as a wedge issue with his political opponents in Canada, at the expense of the country's influence on peace in the Middle East. The Liberal leader called for a return to a time when Canada was perceived to be an honest broker in the global community.
Harper made his remarks at the start of a two-day conference on anti-Semitism that is being held on Parliament Hill during Holocaust Education Week.