Writing for The National Interest, long time Middle East reporter Hussain Abdul-Hussain notes that Saudi Arabia has been appeasing Iran in the face of Iranian attacks on Saudi targets. He argues it would be in the Saudis' interests to get closer to Israel than to Iran.
Abdul-Hussain's article is entitled "Why is Saudi Arabia Appeasing Iran?" It isn't clear if that is his title or if it was retitled by the publication's editor, which sometimes happens. I raise the issue because the article never answers the question posed by its title.
I propose to take an outsider's stab at answering it for him. I see three reasons.
The first reason is location. Iran and Saudi Arabia sit roughly 100 miles apart across the Persian Gulf (aka Arabian Gulf). They live in the same neighborhood.
The second reason is size. Both are big countries with Saudi Arabia somewhat larger. However, the current population estimate for Iran is 93 million, for Saudi Arabia is only 35 million.
Factors of location and relative population size figure into any potential military confrontation, including this one. The last factor is unique to the region.
The third is the hadjj. Islam places an obligation on all believers - who are able - to visit the holy sites in Mecca and Medina. Thus there will inevitably be many thousands of Iranians visiting those Saudi cities every year.
If you live next door to someone whose religion you mostly share, and that faith requires you to host many thousands of their visitors every year, you might not want to take a hostile stance toward that country. Doing so would vastly complicate Saudi security concerns.
For example, closing the Saudi borders to Iranians would be much more than an inconvenience. It might be viewed as interfering with Iranians' sacred duties. Saudis have ask themselves "are we being the hosts Allah wants for his holy cities?" This stewardship factors into many Saudi considerations, foreign and domestic.