On New Year's Day in Al-Ha'ir Prison south of Riyadh, the Saudi Arabian government executed 47 persons whom they declared to be terrorists or heretics. It was the largest mass execution in nearly 40 years. Forty-three were Sunni members of Al-Qaeda affiliates. Four were Shia and essentially irritants to the government, which under Saudi rules qualified them to be executed.  One, Nimr al-Nimr, was a Saudi Shia cleric, originally arrested in 2012 at the height of the so-called Arab Spring, which was deeply unpopular with the Saudi royals.A couple of days later Saudi Arabia broke off diplomatic relations with Iran, because in Tehran and Mashad Shia protesters against al-Nimr's execution were permitted by security forces to invade and then set fire to Saudi diplomatic facilities.The Ayatollah Ali Khamenei, Supreme Leader of Iran, then changed the name of the street where the Saudi facilities were located to Sheikh Nimr Street and announced on his English-language website that “the hand of divine retribution will seize the Saudi politicians by the throat.” He added that the attack on the embassy was “unjustifiable.”Meanwhile several Saudi Arab allies, all Sunni regimes, downgraded or severed diplomatic relations with Iran. Egypt did not and the non-Arab but Sunni-majority states of Turkey and Pakistan also maintained diplomatic relations with Iran.Since then, there has been a Saudi airstrike near the Iranian embassy in Sana'a, Yemen. Iran banned imports from Saudi and reiterated its ban on “umrah” pilgrimages to Mecca, which unlike the Hajj pilgrimage are optional and can occur any time during the year. Four Saudi soccer teams, representing their country at the 2016 Asian Champion League games, refused to play on their Iranian opponents' home fields.Anxieties over a regional sectarian war between Sunni and Shia, however, are overblown. Sectarian hostilities between Saudi and Iran can be traced to the eight-century conflict over the successor to the Prophet, and more recently the Saudis supported Saddam in the eight-year, million-casualty war between Iraq and Iran. For their part, Iran supported the Iraqi Shia following the US-Iraq war and they support the Shia in Syria and Yemen as well. The Saudis are threatened by the possibility of a nuclear-armed Iran, thanks to what they see as American betrayal. In this respect, the Saudis agree with the Israelis, of all people.So the interesting question is: why did the Saudis execute al-Nimr now? The most obvious reason is because they want to challenge not so much the Shia but the Iranians. This matters today because of changes in relations between theUS and Iran and between the Americans and the Saudis. In short, the Saudis deliberately escalated a confrontation into a noisy crisis and used petrodollars to strengthen regional loyalties for specific practical objectives.Those objectives are many: to disrupt the warming trend in American-Iranian and EU-Iranian relations; to remind the Islamic State that Iran and the Shia are higher on their enemies' list than they are; to reduce the possibility of Iran playing a role in any settlement in Arab- and Sunni-majority Syria; to show Iran that it does not tolerate their interference in Sunni- majority and Arab countries.Even so, this diplomatic flare-up is not likely to start a larger war not least of all because the Iranian military is nearly three times the size of the Saudi.The confrontation also carries implications for Canadian foreign policy. The abrupt end of the Saudi kingdom would mean chaos, which brings opportunities for even more obnoxious actors than the Saudi royals. The advent of the Islamic State from the chaos of Iraq clearly shows this. That is one reason why Canada is selling armored vehicles to the Saudis. One must point out, though, that at 22 tons, they do not meet the Prime Minister's description that they are “jeeps.” The vehicles are destined for use by the Saudi Arabia National Guard, which already operates similar Canadian-made vehicles, purchased in the 1990s, for use chiefly in the Shia-majority parts of the kingdom.Whether Canada has any long-term interest in backing either the Saudis or the Iranians is certainly debatable. For the near-term, however, there is no doubt that we are supporting the kingdom.Barry Cooper is Foreign Affairs, Defence, and Trade Policy Chair at the Frontier Centre.