There was lots of debate in the Senate during the passage of the 14th Amendment; much of it revolved around birthright citizenship. Both those who wanted the Amendment to exclude people who were born to those temporarily in the US and those who did not acknowledged that, in the form passed, it did not.

Sen. Edgar Cowan of Pennsylvania said "I am really desirous to have a legal definition of ‘citizenship of the United States. Is the child of the Chinese immigrant in California a citizen?" He didn't think that child should be.

Sen. Conness of California said he thought it should cover "the children begotten of Chinese parents in California, and it is proposed to declare that they shall be citizens. I voted for the proposition to declare that the children of all parentage whatever, born in California, should be regarded and treated as citizens of the United States, entitled to equal civil rights with other citizens of the United States." And let's remember, as Conness was certainly aware, that many of those Chinese laborers had been imported illegally.

They knew what they were passing, and they knew it included birthright citizenship. Senators who wanted to alter the Amendment to exclude some people failed.