The cultural plurality of the Nigerian State has been a major factor in the
make-up of the policy environment as well as policy frameworks of national leadership
from independence. Cultural pluralism could be a uniting or divisive factor, and for
Nigeria, it has been more instrumental in the challenge of nationhood, culminating in a
Civil War, agitations for state creation, sovereign national conference, rotational
presidency, and zoning, and in more recent times, ethnic and religious insurgency as
well as terrorist violence. National integration thus becomes far-fetched as it yet
remains a quest by successive administrations and non-state actors who are
stakeholders in the Nigerian project. But has the context of the external influences and
concerns such as migrants, foreign visitors unaccounted for and unwanted aliens as
well as their activities in the challenge of nationhood been well addressed? This paper
examines the historical and contemporary issues of cultural plurality (often referred to
as multiculturalism, although a little different) in the challenge of national unity, with
particular attention to the security dilemma for Nigeria in the 21st century, paying
attention to the growing influence of the unchecked aliens in the swelling question and
graver dangers of insecurity posed by unconcerned and unpatriotic aliens who flock
into the nation through the porous borders. A descriptive-analytical approach is
applied, while the data are basically collected from texts and academic journals. The
paper submits that the Nigerian State requires an overhaul of its security machines
within and around its borders, while also taking a second and deeper look at its
immigration system.