Driving such discussion is a self-serving narrative, promoted by Israel as well as by Saudi Arabia, about Tehran's purported quest to "destabilize" and, ultimately, "take over" the region.

Assessments of this sort have, of course, been invoked to justify — and elicit Western support for — Saudi intervention in Yemen. More broadly, the Israeli-Saudi narrative about Iranian ambitions is framed to prevent the United States from concluding a nuclear deal with Tehran — or, failing that, to keep Washington from using a deal as a springboard for comprehensively realigning U.S.-Iranian relations.

Determination to forestall Iran's international normalization by hyping its "hegemonic" regional agenda was on lurid display in Israeli Prime Minister Binyamin Netanyahu's much-watched March 3, 2015 address to the U.S. Congress. As Netanyahu warned his audience, "Backed by Iran, Shiite militias are rampaging through Iraq. Backed by Iran, Houthis are seizing Yemen, threatening the strategic straits at the mouth of the Red Sea. … Iran is busy gobbling up the Middle East."