  We study the conditions of propagation of an initial emergent practice
qualified as extremist within a population adept at a practice perceived as
moderate, whether political, societal or religious. The extremist practice is
carried by an initially ultra-minority of Radicals (R) dispersed among
Conventionals (C) who are the overwhelming majority in the community. Both R
and C are followers, that is, agents who, while having arguments to legitimize
their current practice, are likely to switch to the other practice if given
more arguments during a debate. The issue being controversial, most C tend to
avoid social confrontation with R about it. They maintain a neutral
indifference assuming it is none of their business. On the contrary, R aim to
convince C through an expansion strategy to spread their practice as part of a
collective agenda. However, aware of being followers, they implement an
appropriate strategy to maximize their expansion and determine when to force a
debate with C. The effect of this asymmetry between initiating or avoiding an
update debate among followers is calculated using a weighted version of the
Galam model of opinion dynamics. An underlying complex landscape is obtained as
a function of the respective probabilities to engage in a local discussion by R
and C. It discloses zones where R inexorably expand and zones where they get
extinct. The results highlight the instrumental character of above asymmetry in
providing a decisive advantage to R against C. It also points to a barrier in R
initial support to reach the extension zone. In parallel, the landscape reveals
a path for C to counter R expansion pushing them back into their extinction
zone. It relies on the asymmetry of C being initially a large majority which
puts the required involvement of C at a rather low level.
