Riyadh has long had an uncomfortable relationship with the Muslim Brotherhood. But what began as mutual mistrust has now turned to open conflict, with Riyadh outlawing the organisation on 7 March and designating it a terrorist group.

The Brotherhood’s supporters in Saudi Arabia have never before felt the need to hide their association so long as their target was outside the kingdom. Now they are under intense scrutiny across the Gulf. The UAE, in particular, has taken a hard line on its own citizens associated with the Brotherhood, jailing dozens in January. The Egyptian government too, has outlawed the group again, and launched a vicious crackdown on its members.

Outside the kingdom, however, Riyadh will find it difficult to impose its will. Muslim Brotherhood-affiliated parties, and other organisations that share a similar view of the role of Islam in politics, have now become fully integrated into the mechanisms of power.

Libya’s nascent General National Congress and government includes a number of Brotherhood members, and Tunisia’s ruling Ennahda party is sympathetic to the Brotherhood cause, although has stopped short of association. Closer to home, the parliaments of Jordan and Kuwait both host considerable Brotherhood influence.

However, Syria illustrates the challenge. Saudi Arabia has taken a lead in supporting and funding the Syrian opposition, in which Syrian Brotherhood supporters play an important role. Riyadh’s pressure on the group across the region may well encourage the Syrian Muslim Brotherhood to progressively withdraw from opposition politics, and refocus their efforts on social and military activities against Bashar al-Assad’s regime.

As much as the kingdom despises the Muslim Brotherhood, it is now deeply embedded into the region’s political establishment. It will have to keep working with them.