President Trump on Thursday said he had instructed the Department of Commerce to "immediately begin work on a new and highly accurate" census that would exclude undocumented immigrants .

But the census is a massive undertaking and has huge repercussions nationally, including on congressional seat alignment — so it's not something that can be changed quickly. In fact, the Census Bureau said it began planning the 2030 census in 2019.

CBS News has reached out to the Commerce Department for comment on Mr. Trump's post.

Here's what to know about the census process:

The Constitution requires the Census be taken every 10 years

Per Article I, Section 2: "The actual enumeration shall be made within three years after the first meeting of the Congress of the United States, and within eve

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