With a level of speed breathtaking even for an Egyptian political crisis, the Egyptian military’s role has soured in record time since removing Mohammed Morsi from office last week.

On Monday, the Egyptian army gunned down protestors in favor of Morsi and the Muslim Brotherhood, apparently killing at least 51 people in the process.  That came after top Muslim Brotherhood leaders had been detained or arrested in the wake of Morsi’s ouster.  It also comes after the new military-backed administration, headed by interim president Adly Mansour, all but announced (then all but retracted) the appointment of Mohamed ElBaradei, the former head of the International Atomic Energy Agency, as the country’s new prime minister over the weekend.

Both the short-lived ElBaradei appointment and Monday’s brutality have now alienated one of the most surprisingly odd bedfellows out of the coalition that initially supported army chief Abdel-Fattah El-Sisi in pushing Morsi from office — the Salafi movement’s Al-Nour Party (حزب النور‎, Arabic for ‘Party of the Light’), an even more conservative group of Islamists that have long competed with the Muslim Brotherhood for influence in Egypt.  Like other groups that have come to oppose Morsi over the past year, the Al-Nour Party has criticized Morsi for increasingly centralizing power within the ranks of the Muslim Brotherhood, and their backing for Morsi’s removal last week provided El-Sisi and the Egyptian military crucial support from within Islamist ranks.

But in the wake of Monday’s deaths, the Al-Nour Party announced that it was suspending its participation in the ongoing negotiations over Egypt’s political future.  Mansour has now signaled he may appoint Samir Radwan, a technocratic economist and short-lived finance minister in the final days of Hosni Mubarak’s government, as the new interim prime minister, and Mansour yesterday announced an ambitious timetable that would submit the Egyptian constitution to a review committee, submit any revisions to a constitutional referendum within three months, which in turn would be followed in two weeks by the election of a new Egyptian parliament and in three months by the election of a new Egyptian president.

Monday’s bloodshed has increased the pressure on Mansour to bring some semblance of calm to Egypt’s now-chaotic political crisis, with Morsi supporters and followers of the Muslim Brotherhood continuing to demand the restoration of the Morsi administration.

The Al-Nour Party’s leadership is walking a difficult line — on the one hand, it is now well-placed to influence events in post-Morsi Egypt; on the other hand, it’s long been split over how much support to provide Morsi as an Islamist president, some of its supporters opposed Morsi’s removal, and the Muslim Brotherhood will be quick to point out that the Al-Nour Party has turned on its fellow Islamists.  By initially supporting last week’s coup but turning on the new transitional government this week, the Salafists may be trying to maneuver the best of both worlds.  But after a year where the Al-Nour Party has already splintered, its controversial support for the Egyptian military may shatter it further.

But regardless of whether Mansour can somehow bring the Salafists back into the ongoing political process, and regardless of whether the actual Al-Nour Party can manage to form a united front, their Salafist supporters have now become the key constituency in the latest act of Egypt’s existential drama.  After decades of disdain for active politicking, the Salafi movement has shown itself to be a relatively canny political actor in the post-revolution Egypt, and it makes Al-Nour’s leader, Younes Makhioun (pictured above), one of Egypt’s most important politicians.

With the Muslim Brotherhood rejecting Mansour’s timetable and continuing to agitate for Morsi’s return, it’s not clear whether the Brotherhood and the Freedom and Justice Party will even participate in any upcoming elections, even if Mansour manages to avoid delays and carry out three sets of free and fair elections in the next six months. It’s likewise equally unclear whether El-Sisi and the Egyptian military will even let the Muslim Brotherhood contest the elections uninhibited.

Having avoided the taint of being part of Morsi’s ill-fated government and all of its failures — from the November 2012 push to force a new constitution into effect to the ongoing failures of economic policy — the Al-Nour Party stands a strong chance of picking up many of the Muslim Brotherhood’s disillusioned voters as an Islamist alternative.

So who are the Salafists and what would their rise mean for Egypt? 

The Salafi movement, based in Alexandria, first gained significant support in the 1970s as an alternative to the Muslim Brotherhood’s increasingly political role in Egyptian life.  Mubarak often found it useful to use the Salafi movement as a foil against the Muslim Brotherhood during his three decades in power — after all, Mubarak would obviously favor a movement that eschewed direct engagement in politics.  An exclusively Sunni movement, they would likely be even more hostile to Shi’a Muslims than the Morsi administration has been, and they would likely take a harder line against Iran’s Islamic Republic than the more balanced approach that Morsi favored.

As Nathan J. Brown explains in When Victory Is Not an Option: Islamist Movements in Arab Politics, the key differences between Salafists and more mainstream Islamists involve the appropriate role of Islamists in politics:

First, their interest in correct interpretations of texts and following appropriate practice trumps all other concerns. (I have sometimes heard ‘textualist’ — nususi — used as a synonym for Salafi).  In contrast to the more freewheeling approach of Islamists, with their willingness to admit many interpretations as plausible, Salafis strive to find the best possible (and therefore correct) reading and apply it to personal behavior.  Second, Salafi movements tend to be far less formally organized as a matter of choice.  Third, they tend to be much less committed to involvement with the broader society.

But the Al-Nour Party has strayed far from all three of those general characteristics since the Egyptian revolution began, and it’s shown a surprisingly canny approach to engaging Egyptian political life.

Although the Al-Nour Party ultimately backed Morsi in the runoff against former Mubarak air force chief Ahmed Shafiq in the June 2012 presidential race, it initially supported Abdel Moneim Aboul Fotouh, despite the fact that Aboul Fotouh, a former Muslim Brotherhood member, was running as a more moderate Islamist than Morsi willing to bridge the worlds of Islamists and liberal reformists.  Furthermore, despite the strictest interpretations that would otherwise forbid traditional Western lending practices, the Al-Nour Party has proven equally flexible with respect to providing conditional approval to a loan from the International Monetary Fund to shore up Egyptian finances.

Nonetheless, there’s really no way to know how a Salafist government, once in power, would try to rule.  Morsi and the Muslim Brotherhood, after all, came to power promising a broad-based and inclusive government, though it became increasingly Islamist in its outlook and increasingly narrow in its outreach.

In the last set of parliamentary elections held in Egypt at the end of 2011 and the beginning of 2012, the Muslim Brotherhood’s Freedom and Justice Party (حزب الحرية والعدالة‎) won 37.5% of the vote and the largest bloc (235) of the 498 parliamentary seats, but the Al-Nour Party won 27.8% of the vote and 123  seats.  No other political party in Egypt at the time won more than 40 seats.

The Al-Nour Party isn’t quite as united as it was back then, though, with Salafists divided during the Morsi administration over the appropriate level of support for an Islamist president and now, also divided over whether to back the Egyptian military’s actions last week.  Former Al-Nour Party leader Emad Abdel Ghaffour had increasingly clashed with Yasser Al Borhamy, one of the Salafi movement’s most important spiritual leaders, and Ghaffour left the party in December 2012 to start his own competing faction, the Al-Watan Party (حزب الوطن‎, Arabic for ‘Homeland Party’).  Ghaffour, who had been appointed as a Morsi advisor on social outreach, had always favored closer collaboration with Morsi and he and his allies opposed the military’s coup last week.  Ghaffour’s allies include the populist Salafi preacher Hazem Salah Abu Ismail, who was a leading candidate for the presidency in spring 2012 before his disqualification by the Supreme Council of the Armed Forces.  Abu Ismail himself is reported to have been arrested on July 5 for inciting violence.

Meanwhile, the liberal and secularist movement is more united than it was 18 months ago in light of ElBaradei’s formation in November 2012 of the  National Salvation Front (جبهة الإنقاذ الوطني‎) in league with former Arab League secretary-general Amr Moussa and Hamdeen Sabahi, a popular ‘Nasserite’ leftist former presidential candidate.

Despite those dynamics, the Al-Nour Party commands the strongest and most committed support within Egypt except perhaps the Muslim Brotherhood and like the Muslim Brotherhood, the Salafi movement can draw on the goodwill that it’s developed over decades through civil society programs that have  provided not only religious guidance but support for Egypt’s poor.

All of which means that after all the Sturm und Drang of removing Egypt’s first directly elected Islamist government last week, El-Sisi and the Egyptian military may well be putting in place a process that smooths the way for the election of an even more conservative Islamist government.