The international response to the growing political crisis in Yemen was initially muted. The US president, Barack Obama, urged Mr Saleh to follow up his pledges of reform with "concrete actions". However, behind the mild rhetoric, there was clearly some concern within US policymaking circles. In mid-February the director of national intelligence, James Clapper, told the House of Representatives' intelligence committee that the deteriorating situation in Yemen will "present serious challenges to US and regional interests, including leaving AQAP [al-Qaida in the Arabian Peninsula] better positioned to plan and carry out attacks".

There is no doubt that the protests have added an extra dimension to Yemen's myriad travails and Mr Saleh cannot treat them as he has other anti-regime groups, which he can typically paint as extremists or separatists. On this occasion, the vast bulk of the protesters are ordinary, disaffected Yemenis. However, there is one important difference to Egypt that will greatly assist Mr Saleh's efforts to weather the current crisis. When Mr Mubarak warned Egyptians that chaos would ensue if he was ousted, his words were mostly ignored. In contrast, in Yemen there is a much greater possibility of anarchy if Mr Saleh falls. Although the president may be the architect of many of Yemen's present problems, he is also the person who has kept the country together throughout his tenure. It is inevitable that at least some Yemenis will fear the prospect of chaos more than they despair of Mr Saleh's rule-a calculation that may only be further sharpened in light of the bloody uprising in Libya (which arguably shares more of the tribal and socioeconomic hallmarks of Yemen, than Egypt and Tunisia).

Either way, the US and Saudi Arabia will be watching Yemen's turmoil closely. Both countries consider Yemen a major source of international terrorism, and the possibility of the country falling into political limbo, where AQAP is free to operate, will seriously unnerve US and Saudi officials. However, the US faces a particularly tricky moral conundrum (as it did during the Egyptian revolution). Although US foreign policy in the region has tended to err in favour of stability over liberty, it will equally be loath to place itself on the side of Mr Saleh's weakening regime-a stance that would alienate the mass of protesters currently calling for greater democracy and accountability.