Final answer:
True, some societies practice cousin marriage to create political and military alliances. This strategy played a significant role in the historical expansion of European empires by securing native allies, such as in the Spanish conquest of the Aztec. The practice varies globally based on cultural norms and incest taboo.
Step-by-step explanation:
Some societies do indeed practice cousin marriage as a way to establish political and military alliances with neighboring communities. This practice of forming alliances through marriage has been historically significant, and it helps to create united fronts or strengthen familial ties between groups. Indian alliances, for example, were essential in establishing power for European empires in the southeast. This strategic move was true, as having native allies was a critical factor in the success of European colonization and expansion efforts, such as the Spanish conquest of the Aztec.
Additionally, such marriages can also be about preserving certain qualities within a community, as seen in some tribal societies where marrying within the group helps to maintain a higher blood quantum for tribal membership. This practice of cousin marriage is subject to cultural norms, and it varies widely across the globe, with some societies enforcing a strict incest taboo that includes first cousins while others do not.