The ACLU of Northern California says they cannot deny you entry. https://www.aclunc.org/our-work/know-your-rights/know-your-rights-us-airports-and-ports-entry

The ACLU of Northern California says they cannot deny you entry. https://www.aclunc.org/our-work/know-your-rights/know-your-rights-us-airports-and-ports-entry https://www.aclunc.org/our-work/know-your-rights/know-your-r... U.S. Citizens: You only have to answer questions establishing your identity and citizenship (in addition to customs-related questions). Refusal to answer other questions may cause delay, but officials may not deny you entry into the U.S. if you have established your identity and citizenship.