I thought the Sunnis and Shiites were implacable foes. Can we believe this?
They have a lot more in common with each other than either group has with us. It would be like saying Baptists and Catholics are incompatible. Well, they might have their differences but those are NOTHING compared to their differences with Islam.
“I thought the Sunnis and Shiites were implacable foes”
With the exception of about a 5 or 6 year cooling period, Iran has been supporting Hamas (sunnis) for decades. They have cooperated with & supported sunni militant groups for decades, including AlQaeda. Never forget that they allowed transit of AlQaeda members thru Iran who were involved in 9/11.
“Can we believe this?”
Iran & Saudi Arabia had mostly friendly diplomatic relations for almost 50yrs, until 1979 when Khomeini took over. It’s been mostly adversarial since, with short periods of cooling of tensions. So, could this be another cooling period...possibly. But if it happens, I doubt it would last long at all.