Why would Trump want to use the census to dilute the power of Texas -- the biggest Republican state?

The Trump administration wants to exclude undocumented immigrants from the population counts used to determine seats in Congress, an idea that would cut into the strength of the Texas delegation to Washington, D.C.

About 6% of the people in Texas are undocumented immigrants. They work and live in the state, and they pay taxes. They’re not citizens, and they can’t vote.

Their presence in Texas increases the population of the state, and the number of people Texas sends to Congress is directly tied to the number of humans in the state. Not just voters, not just citizens. Humans.

The Trump administration wants to keep noncitizens out of the count used to determine how many people Texas sends to Congress. Undocumented immigrants may not be voters, but excluding people who live in and contribute to society is both undemocratic and unrepresentative. And it’s not about participation. We count kids, after all, because people who live under the laws made in Washington need elected advocates even if they can’t vote.

And this is a head-scratcher, if viewed through this lens of partisan politics: The Trump administration is backing a move that would shrink the power of the biggest Republican state in the U.S.

The move also seems out of line with the language in the U.S. Constitution: “Representatives shall be apportioned among the several States according to their respective numbers, counting the whole number of persons in each State, excluding Indians not taxed.”

Sure enough, a coalition led by Common Cause filed a legal challenge Friday, and others are expected to follow.

Only California has a larger undocumented immigrant population than Texas. Between them, those two states are home to an estimated 38.9% of the 10.6 million undocumented immigrants in the U.S. And those two states — the biggest Democratic and Republican states in the union for the last several elections — would take the biggest hit in Congress and in the number of votes they cast in the Electoral College in presidential elections.

None of the proposed counting change would affect the 2020 elections, so there’s nothing in it for this president in November. But it will affect the balances in the next race, and in Congress after the 2022 elections.

Texas would, under the proposal, lose clout. So would California. What’s more, legislative and congressional districts within the state could be significantly different if redistricting maps were based on counts of citizens instead of population totals.

Here’s how this works right now. You count the national population every 10 years. You divide that number by 435 — the number of seats in the U.S. House — and you apportion those seats to the states, based on the number of people per congressional seat found in the first calculation. There’s some rounding, and each state, no matter its population, is guaranteed at least one seat in the House.

Based on the reapportionment that followed the 2010 census, Texas has 36 congressional representatives in addition to its two U.S. senators. By some estimates, growth in the population here — relative to other states — could add three seats to the delegation after the reapportionment that follows the 2020 census.

But that’s only if all of the people in the state count for purposes of representation. An estimated 1.8 million undocumented immigrants lived in the state in 2018. That’s enough people for more than two congressional seats; if they weren’t counted, Texas would be entitled to 34 seats in the House instead of 36.

Those are estimates. A practical problem with the new proposal is that the government was already barred from including citizenship questions in the census; how it would determine the number of people to include as citizens without such a question isn’t clear.

In a letter urging Texas Attorney General Ken Paxton to take legal action to stop the proposal, state Rep. Chris Turner, D-Grand Prairie, framed the idea as an attack on Texas.

“Filing suit to block the Presidential Memorandum to the Secretary of Commerce dated July 21 would be wholly consistent with your official biography that explains as Attorney General, you are ‘focused on protecting Texans and upholding Texas laws and the Constitution’ and ‘fighting federal overreach.’ Indeed, if unchallenged, the President’s actions would likely hurt Texas more than any other state.”

The partisan politics here are clear enough. Turner is the chairman of the Texas House Democratic Caucus. Paxton, a Republican, is the newly branded co-chair of the national Lawyers for Trump.

But not all that is political is partisan, even in an election year. Does anyone in elected office here think Texas should have less influence in Washington, D.C.?