Critics of blood quantum argue that applying such strict rules for membership will inevitably destroy Native American tribes completely. According to the Native Governance Center, this is borne out by statistical projections indicating that many tribal groups will see a rapid decline in numbers in the near future. Aside from demographic issues, blood quantum rules also put many Native Americans in a difficult situation in regard to love and marriage. Many people feel obligated to date within their tribe — falling in love with a person of another race could mean their children do not get to partake in their Native American heritage (via NPR).
Changing blood quantum rules would be an easy way to ensure the survival of Native American communities. Back in 2004, a suggested proposal to lower the blood quantum for the Navajo Nation from ¼ to ⅛ would have almost doubled tribal membership from 310,000 to 600,000 (via Indianz). Similarly, a 2011 study found that although there were only 16,924 registered members of the Blackfeet Nation, over 105,000 people claimed to have Blackfeet ancestry in the census (via Great Falls Tribune).
Native Hawaiians, like Native Americans, also deal with significant issues caused by blood quantum measures. In Hawaii, a 50% blood quantum comes with significant land rights, and the issue of blood quantum has resurfaced repeatedly as part of a tense political debate surrounding land use (via Public Radio Hawaii).