Ostensibly, the arrest was prompted by critical remarks in Sh. 'Ali's Friday sermon. A contact in al-Wifaq says the government was particularly upset by the following bit claiming that Bahrain's ills started "with the arrival of the Al Khalifa" -- i.e., in 1783:
As always, the political message of Sh. 'Ali's arrest has multiple intended recipients, corresponding to the state's various core constituencies. The most important of these two are Bahraini Sunnis and Western governments. As I've written elsewhere, the first can be divided further into two basic groups: Sunnis with a primary security orientation, and Sunnis with a potentially oppositional political orientation. One can connect the timing of the arrest to present developments relating to all three constituencies, in addition to al-Wifaq itself.
The arrest and prosecution of top al-Wifaq officials, including not only 'Ali Salman but also 'Isa Qasim, has been the primary demand of the state's security-minded supporters since the beginning of the uprising. Until now, the state has resisted taking this step, and these citizens have had to content themselves with the imprisonment of Nabeel Rajab and other high-profile activists generally from outside al-Wifaq. Why this policy has changed now is difficult to ascribe to a single cause.
It may simply be, for instance, that security-minded figures within the Al Khalifa continue to gain influence and strength at the expense of more moderate officials. It is also possible that the recent spate of improvised explosive devices being used against police -- two of whom were severely injured in Maqsha'a on the very night of 'Ali Salman's sermon -- has led to more pressure to act from within and outside the government. (According to my 2009 survey, around 1 in 8 Sunni households has at least one member employed in the police or military.) Perhaps coincidentally, Bahrain also announced on Monday its most recent acquittal of police officers accused of torture, including in this case one Al Khalifa princess.)
Certainly, the Arabic-language press in Bahrain is making a clear connection between Sh. 'Ali's arrest and the "terrorist violence." Consider the screenshot above of today's Page 1 in Al-Ayam, which has an article of the arrest flanked by two others: one reporting on a grenade attack in Dumistan and thwarted "car bomb" in Manama; another on Hizballah's "assassination" of Sunni politician Mohamad Chatah in Lebanon.
Whatever the case, the arrest seems to have done the trick for at least some Sunnis in Bahrain. A thread on the main pro-government forum contains this celebratory GIF of a dancing 'Ali Salman:
Others, though, were less satisfied. "Too bad Bahrain isn't part of Saudi Arabia [i.e., as part of a Gulf Union/federation]," remarked one commenter, "since then we'd have the death penalty."
Alternatively, one could proffer another explanation entirely, which is that the arrest comes as a useful distraction from another notable political event: a looming parliamentary battle over a government plan to reduce fuel and other subsidies that threatens to expose a range of economic-cum-political grievances. (One will recall, of course, that following al-Wifaq's resignation the present parliament is composed of nominally "pro-government" (mainly Sunni) politicians who are not looking so pro-government at the moment.)
Whereas Al-Ayam leads with the story of 'Ali Salman's arrest and continuing violence, the front page of the Gulf Daily News dedicates most of its real estate to the legislative "showdown":
The arrest of the al-Wifaq leader, by contrast, barely makes the front page.
It goes without saying that all this takes place in the context of fragile US-Gulf relations amid discord over (relative) Western détente with Iran. Secretary of Defense Hagel was keen to stress continued and even expanded American military cooperation with Bahrain in recent remarks at the Manama Dialogue; while the New York Times reported earlier this month possible concessions to Gulf states demanding early access to advanced military hardware -- airplanes, in this case -- normally withheld to preserve a strategic advantage for Israel.
Under such circumstances, the present political leverage enjoyed by Bahrain and especially patron Saudi Arabia may also play into their willingness to risk a potential diplomatic encounter over heightened persecution of the formal opposition in Bahrain.
Finally, it is worth considering the authorities' message to al-Wifaq and 'Ali Salman itself, beyond the obvious "stop slandering the government and inciting violence." This is important especially in the context of a potential political bargain in the short or medium term.
The message would seem to be that al-Wifaq must take responsibility, and will be held responsible, for actions even of those activists nominally outside its control. This question -- the matter of al-Wifaq's sway over the "Shi'a street" -- is a critical one for any possible political solution. For if the group cannot credibly promise to end opposition protest and violence, even by (at least a majority of) those who do not subscribe to its political program, then the government has no incentive to negotiate in the first place, since in any event its interlocutors cannot deliver what it wants.
Update: Al-Wasat reports that 'Ali Salman has been released from detention, though his travel ban will remain pending trial.
Update 2: A contact who met with Sh. 'Ali on Sunday tells that he had this to say about the arrest:
- The authorities "want to apply [the] brakes on opposition" activities inside and outside Bahrain.
- Plans "were underway for travel to several places, including EU, US, GCC and Russia."
- "Officials overlook [the] consequences of their actions," the questioning having "brought Bahrain again under [the] international spotlight."
Update 4: No story is complete without a pseudo-academic analysis from Bahrain's most noted Czech-based pseudo-academic slash obscure journal editor (who may or may not exist) Mitchell Belfer, who brings his usual gravitas and linguistic precision to "The 'Who' and the 'Why' of the Plotted New Year’s Eve Massacre in Bahrain."