Iran protesters
Iranian protesters demonstrate outside the Saudi embassy in Tehran over the execution of Shia Muslim cleric Nimr al-Nimr by Saudi authoritiesGetty

Saudi authorities were not always so rash. A governing elite that for decades prided itself on caution and keeping a low profile has, with the execution of popular cleric Sheikh Nimr al-Nimr, embraced a posture of bellicose irresponsibility.

When Saudi officials carried out his death sentence on 2 January, they knew that their beleaguered Shia population would take to the streets. They knew that they were undermining the viability of a recently opened embassy in Baghdad. They knew that diplomatic relations with Iran, already at their most fragile, would devolve, and possibly be suspended entirely. They knew that they were heightening tensions in the region's developing cold war.

They knew, and they chose the reckless approach anyway. Saudi officials no doubt felt safe in the inevitable non-response from their two biggest backers and weapons suppliers. Sheikh Nimr's execution stoked the kind of domestic and regional conflict that benefits the Saudi government in the short term while severely impinging on the US and UK's shared interest in maintaining stability and reducing sectarianism in the Gulf. In response to this undermining of longstanding foreign policy objectives, the US and UK reverted to the passive voice, delivering statements of muted caution that failed to distance themselves from an ally turned agent-provocateur.

Both foreign ministries seemed loathe even to mention the man whose execution touched off the latest wave of regional instability.

It took US Department of State Spokesperson John Kirby took four paragraphs to express that his government is "particularly concerned that the execution of prominent Shia cleric and political activist Nimr al-Nimr risks exacerbating sectarian tensions."

The UK's Tobias Ellwood, minister for the Middle East, could not bring himself to mention Sheikh Nimr at all, instead reiterating the UK's opposition to the death penalty.

These statements are all too representative of the nations' shared approach to their troublesome ally. Cowed by the Saudi government's frequently acidic pushback, spokespeople settle for vague unease instead of impactful criticism. Disappointment is expressed, and "particular" concerns —apparently the sharpest of the diplomat's tools — are raised. Meanwhile, the governments sell billions' worth in weapons as their leaders make statements of fidelity that belie the alliance's common characterization as self-interested and functional.

When Saudi elite sought to keep their myriad of human rights abuses in house, this royal deference made some tactical, if not moral, sense. Current Saudi leadership, however, appears set on leveraging domestic violations for foreign outrage, a stance that its allies should no longer address with active negligence.

Saudi citizens will experience the results of this negligence most acutely. Citizens of the economically and politically marginalized Qatif province have renewed their protests, with violent consequences.

When demonstrations began in 2011, Sheikh Nimr, then free of prison, spurred them on, telling locals that they would counteract governmental oppression with the "roar of the word"; Saudi authorities met these protests with the roar of live ammunition. The continuation of this violence will feed the prejudicial notion found in much of Saudi society that Shia in Qatif and the wider Eastern Province represent an Iranian fifth column, thereby bolstering acceptance of the status quo.

Saudi media will not broadcast Sheikh Nimr's opposition to the al-Assad regime in Syria or his statement that "[if] you're a Shia, don't oppress the Sunni... if you oppressed the Sunni while you're oppressed, Allah would hate you." They will, however, repeatedly play video of renewed demonstrations in Qatif for the purpose of rallying hardline support for a monarchy endangering its position with the execution of Sunni militants and the introduction of economic austerity.

While Saudi citizens suffer, the government's rash actions guarantee that conservative forces in Riyadh and Tehran receive a short-term boost. In executing Sheikh Nimr, a figure that senior Iranian governing officials have vocally supported (even as he has not always returned their favour), Saudi authorities counted on overreaction and condemnation.

They got it, in the form of a mob that attacked the Saudi Embassy in Tehran. With that, Saudi Arabia and its most dependent allies had the pretext they needed to cut diplomatic ties with their antagonistic neighbor, setting off a war of words that will play well in respective newspapers while doing nothing to advance justice or reconciliation.

Meanwhile, the people of Syria and Yemen, caught within Saudi-Iranian wars by proxy, are as far as they have been from the political settlements that will end their respective catastrophes. Over the weekend, the Saudi-led coalition in Yemen announced the end of a tenuous ceasefire violated by all parties to the conflict. UN Secretary-General Ban Ki-Moon felt the need to urge both sides to reduce tensions and support Syria peace talks. Worsening Saudi-Iranian tensions place the resolution for both crises further out of reach than it was on Friday.

Sheikh Nimr's execution also rekindled protests in Bahrain, whose authorities have a record of violence against their people. Throughout the region, the militant voices of militia leaders competed with the reactions of moderates like Ali al-Sistani. The cold war, one not born of "ancient hatreds" but modern oppression and stark power calculations, is sinking to a new low. In the face of this deterioration, the US and the UK are prepared to speak of "sectarian tensions" as if they are born out of the ether, not increased by Saudi action.

The US and UK must prevent their Saudi allies from dragging them into this irresponsible provocation. It would involve forthright condemnation of the execution of a non-violent dissident with a cross-sectarian message. It would continue with an investigation into the likely use of US and UK-manufactured weapons in a Saudi-led foreign adventure.

It must begin, however, with a simple recognition on the part of Saudi Arabia's most important allies: this generation of Saudi leaders is more reckless than the last. Riyadh is unconcerned with upholding US and UK interests. To reassert their position and restore stability, the US and UK will have to express more than vague awareness of Saudi incitement.

Husain Abdulla is executive director at Americans for Democracy and Human Rights in Bahrain, aWashington DC based advocacy group.