The January 2 execution by Saudi Arabia of 47 people on terrorism charges and the backlash it provoked have sent shockwaves through the diplomatic and political landscape of the Middle East. Forty-three of the condemned were Sunni extremists, mostly associated with al-Qaeda. However, four were Shia activists, including the prominent dissident cleric, Nimr al-Nimr, who had emerged over the past few years as a leader of the protest movement among Saudi Shias in the restive and oil-rich Eastern Province. Nimr’s execution has significantly inflamed the already volatile sectarian tensions throughout the region, and led to a diplomatic crisis between Saudi Arabia and Iran – each backed by their allies – that will almost certainly prove difficult to repair and possibly even contain.

The Iranian response to Nimr’s execution was as predictable as it was irresponsible. The Saudi embassy in Tehran was sacked and burned by mobs clearly acting with the acquiescence, if not the approval, of the Iranian government. Targeting foreign embassies has been a favored way of expressing dismay by the Iranian regime since the establishment of the Islamic Republic in 1979, beginning with the targeting of the American embassy and its staff. Since then, there have been numerous instances in which Iran has expressed its objections to the actions or policies of other states by attacking their embassies in Tehran. So it’s not surprising that the Saudi embassy met the same fate over the weekend, although there are reports that Iran, which is seeking greater international acceptance, has apologized for the attack and promised the UN Security Council that diplomatic missions will not be targeted in the future.

The Saudi response – breaking diplomatic relations with Iran – raises the stakes even further. Long-time regional rivals, there had been recent signs of some thawing of tensions between Riyadh and Tehran. The two sides were beginning to talk to each other about a substantive issue of grave disagreement for the first time in years on the periphery of Syrian peace talks. Moreover, Saudi Arabia was preparing to send a new ambassador to Iran, and had just dispatched an ambassador to Iraq after some 25 years of prolonged estrangement.

All of that apparent progress has been overtaken by events of recent days. From the American perspective, a whole series of complications now arises, involving not only the search for peace in Syria, but also the campaign against ISIL, efforts to end the conflict in Yemen, and important diplomacy on issues in Iraq, Lebanon, and elsewhere in the region.

The timing of the executions isn’t easy to explain. But several crucial factors are clear. The most important is that Saudi Arabia almost certainly acted with an awareness of the potential implications the execution of Nimr was likely to have among Shias throughout the region. The messages Saudi Arabia appears to be trying to send to multiple audiences are therefore intelligible.

First, Iran and its allies have once again, and perhaps more starkly than ever, been put on notice that Saudi Arabia is not only prepared for region-wide standoff, but is even willing to raise the stakes. It is a defiant gesture by Riyadh, and in keeping with a policy initiative being pursued by King Salman since his ascendancy that emphasizes greater Saudi resistance towards Tehran and its regional ambitions. It is significant that Nimr was arrested in 2012 and sentenced to death in 2014 under the reign of Salman’s predecessor, King Abdullah, but was not executed. This is, therefore, another example of a change in policy driven by the new king, seemingly with the support of Crown Prince and Interior Minister Mohammed bin Nayef and, one must assume, his son Mohammed bin Salman, the youthful but hawkish defense minister and deputy crown prince.

Second, Shia dissidents in the Gulf Arab states, including in Saudi Arabia itself, as well as Bahrain and elsewhere, are being clearly told that there are strict limits to how much dissent will be tolerated. Joseph Braude has explained the Saudi government’s attitude towards Nimr, and its perception of him as a dangerous and violent subversive, which helps explain why he was executed despite the predictably negative consequences. A different, and also useful, perspective on the rise of Nimr to prominence was recounted in the now-defunct “Riyadh bureau” website. Both perspectives are worth considering, along with others. Nimr aside, the status of Shias in Saudi Arabia must be addressed or it will remain a source of instability in the Kingdom for the foreseeable future.

Third, the vast majority of those executed were Sunni extremists associated with al-Qaeda. The message to Sunni extremists and self-described “jihadists” is a familiar one: their activities inside Saudi Arabia will be met with the harshest penalties. ISIL, too, is a target, since the execution of Shia activists, including Nimr, will have the effect, even if unintended, of undermining the group’s claims to be a Sunni “vanguard” against Shia assertiveness in the region. The blow to Sunni terrorists is therefore two-pronged: first is the fact of the executions themselves and all that they imply about the willingness of the Saudi authorities to crack down on extremists; second is a political attack on the sectarian claims of the terrorists.

One possible explanation for the decision to execute Nimr and other Shia activists at this time is that the Saudi government did not want to be perceived as simply targeting Sunni extremists by executing 43 al-Qaeda members. By executing Nimr and the other three Shia activists, Riyadh may have been attempting to appear “evenhanded.” This is especially plausible given the recent establishment of an Islamic antiterrorism alliance, and other Saudi-led initiatives targeting ISIL and al-Qaeda. But if so, the attempt at balance may have only succeeded in the narrowest possible domestic context, while regionally and internationally the execution of Nimr overshadows all other aspects of the event.

Fourth, the United States is once again being reminded that Saudi Arabia has concluded that American leadership is lacking and that it will pursue its internal security and regional interests in a more proactive and independent manner than it has in the past. Although there were many warnings in recent weeks that a wide-scale Saudi execution was in the works, most Western diplomats and multinational organizations did not expect Saudi Arabia to put Nimr to death. Washington is likely to move quickly to try to ascertain what Saudi Arabia is hoping to accomplish through this action and to begin to repair the perceived damage done to the key American foreign policy concerns cited above. No one should be surprised if Secretary of State John Kerry personally visits Riyadh in the very near future, since this is both his leadership style and would clearly be warranted by the gravity of the diplomatic and political crisis and its impact on the efforts to begin negotiations on Syria.

Saudi Arabia faces significant problems on multiple fronts, including new and serious domestic and foreign policy concerns. Its economy is suffering considerably from the low cost of petroleum, which, for complex reasons, Riyadh itself is helping to maintain. Current tensions with Iran don’t bode well for stability of oil pricing either. This economic pressure on the Saudi social and political system may help to explain the timing of the executions. The Saudi government faces a period of unprecedented belt-tightening, with unavoidable cuts in public services, amenities, subsidies, and other social benefits that the citizenry has come to expect over recent decades. Potential domestic discontent over this new period of quasi-austerity in Saudi Arabia cannot be allowed to spill over into challenges to the system. Therefore, the government may have been prompted to send a clear signal at this moment to Sunni extremists and Shia dissidents alike that any efforts to take advantage of the developing economic and social challenges will not be tolerated. Moreover, the Saudi-led Arab intervention in Yemen appears bogged down, even as reports surface that the Saudi-backed Jaysh al-Islam opposition group in Syria has suffered a series of recent setbacks since the killing of its leader, Zahran Alloush, apparently by a Russian airstrike in December.

Yet the Saudi attitude, as expressed in the executions and subsequent policy decisions, appears to be highly confident, if not brash. Other states have joined Saudi Arabia in breaking ties with Tehran, including Sudan and Bahrain. The United Arab Emirates and Kuwait, however, merely downgraded their ties to Iran – a move that is easily reversible – while fully maintaining trade links. And, as a useful reminder of the diversity within the Gulf Cooperation Council, Oman publicly criticized the Saudi move.

Nonetheless, Saudi Arabia may come to welcome American engagement (if it materializes) on these issues in the coming weeks, especially if Riyadh begins to feel that the consequences of its actions are less manageable than it had anticipated. The complete severing of diplomatic ties with Iran leaves Riyadh little wiggle room to resume high-level diplomacy without some kind of public explanation of what has changed. That could prove politically awkward even if it becomes desirable as policy. The internal blowback within Saudi Arabia is already problematic, with at least one Shia protester killed in Qatif in clashes with the authorities. The White House says it warned Saudi Arabia about the consequences of executing Nimr. Should Riyadh be persuaded that Washington is prepared to reengage in these issues with the Kingdom’s best interests in mind, this could reduce the current level of tension in U.S.-Saudi relations and perhaps repair whatever damage has been done to prospects for greater regional stability.