The procession is intended to show unity against terrorism following the shooting on March 18, as Nidaa Tounes, the leading party of the governing coalition, faces rising internal divisions. Nidaa Tounes has seen off the first major rebellion within its ranks, as a group of outspoken figures mounted a failed challenge against the party leadership in recent months. This was driven partly by frustration at sharing power with Islamists in the coalition government -- it was forced to include Ennahda after its bid for a mainly Nidaa Tounes government failed.
Security reform is now the priority policy.
Yet divisions may affect government efforts to tackle the worsening jihadist threat.
Pressure for a tougher counterterrorism policy from within the government and in the media will mount.
This could lead to curtailments of civil liberties.
