An executive order signed last week by President Trump that would exclude undocumented immigrants from the decennial reapportionment process would cost the nation’s three largest states at least one seat in Congress, a new analysis finds.

It is unclear how the Trump administration plans to alter any final census figures, or what datasets they would rely on to determine how many undocumented immigrants live in each state. Most legal scholars believe the order will not stand up in court.

But if it were to stand, it would likely mean Texas and Florida would each gain one fewer seat in the House than they are projected to, based on recent population trends. California, the home of more undocumented immigrants than any other state, would lose an additional seat as well.

A study conducted by the Pew Research Center projects Texas would gain three seats in the next round of apportionment, and Florida two seats. If Trump’s executive order were to take effect, Texas would likely gain only two seats, and Florida one.

California is already likely to lose one of its 53 seats in the House, the first time since it became a state that its delegation would decline. Under Trump’s executive order, California would lose two seats.

On the other hand, three states likely to lose out would add seats, according to Pew’s math: Alabama, Minnesota and Ohio, all projected to lose a seat in the next round of apportionment, would get to keep their current delegations.

The decennial reapportionment process follows each decade’s census, when the Commerce Department formally notifies Congress of the number of people living in each state. The Constitution requires apportionment to be based on “the whole Number of free Persons,” not including “Indians not taxed.”

Trump’s order has raised questions about how it would be implemented because the census does not ask whether respondents are citizens. The Supreme Court last year struck down the Trump administration’s push to include a citizenship question. No other government agency keeps track of undocumented immigrations in a formal dataset.

Before the order took effect, recent population trends suggest five other states — Arizona, Colorado, Montana, North Carolina and Oregon — are likely to gain one seat each beginning in 2022. Illinois, Michigan, New York, Pennsylvania, Rhode Island and West Virginia are all projected to lose seats, along with Alabama, Minnesota, Ohio and California.