The Fourteenth Amendment confers citizenship on those born or naturalized in the United States. Congress does not have express or implied power to alter or remove citizenship granted under the Fourteenth Amendment unless the person consents. A citizen can voluntarily relinquish citizenship.
Congress may validly pass a statute that imposes conditions on citizenship created outside the Fourteenth Amendment. Such a statute must neither violate constitutional restrictions nor be unreasonable, arbitrary, or unlawful.