Update: President Trump responded to the Supreme Court's decision to block the citizenship question, tweeting Thursday afternoon: "Seems totally ridiculous that our government, and indeed Country, cannot ask a basic question of Citizenship in a very expensive, detailed and important Census," adding that he is asking White House lawyers if the 2020 census can be delayed until the Supreme Court can consider "additional information from which it can make a final and decisive decision."

.....United States Supreme Court is given additional information from which it can make a final and decisive decision on this very critical matter. Can anyone really believe that as a great Country, we are not able the ask whether or not someone is a Citizen. Only in America! — Donald J. Trump (@realDonaldTrump) June 27, 2019

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The US Supreme Court dealt a blow to the Trump administration on Thursday, backing lower court decisions which found the government's reasoning for placing a citizenship question on the 2020 question to be "invalid."

Chief Justice John Roberts joined the liberal justices in a 5-4 ruling in the Dept. of Commerce v. New York, in which the state of New York sued over the hot-button question.

BREAKING: In 5-4 decision, the Court sends the #CitizneshipQuestion back to the agency for another explanation and rules they cannot put the question on the census at this time. #Census pic.twitter.com/WzL1EB1QwB — Legal Defense Fund (@NAACP_LDF) June 27, 2019

The Trump administration argued that the citizenship question is necessary to better comply with the voting rights law, while critics say it is an attempt to intimidate households with illegal immigrants into declining to answer the census.

With fewer people filling out the census, legislative seats are more likely to garner Republican Congressional districts through gerrymandering. -RawStory

In April, President Trump tweeted "Can you believe that the Radical Left Democrats want to do our new and very important Census Report without the all important Citizenship Question. Report would be meaningless and a waste of the $Billions (ridiculous) that it costs to put together!"

Can you believe that the Radical Left Democrats want to do our new and very important Census Report without the all important Citizenship Question. Report would be meaningless and a waste of the $Billions (ridiculous) that it costs to put together! — Donald J. Trump (@realDonaldTrump) April 1, 2019

The Trump administration, meanwhile, asserted executive privilege over materials related to the citizenship question, which Chief Justice Roberts thought was insufficient.

"The sole stated reason -- seems to have been contrived. We are presented, in other words, with an explanation for agency action that is incongruent with what the record reveals about the agency's priorities and decisionmaking process," Roberts wrote.

The data obtained from the 2020 census will be used to allocate congressional seats, as well as the distribution of billions in federal funds to states and localities over the next decade, according to CNN.

Whether or not the administration will be able to reinsert the citizenship question in time for the 2020 Census, with different justification, seems to be the question hanging over #SCOTUS’ decision. — 𝕎𝕖𝕝𝕝𝕤 𝔻𝕦𝕟𝕓𝕒𝕣 (@WellsDunbar) June 27, 2019

Gerrymandering

Separately, the USSC left the topic of gerrymandering to the states - with Roberts writing "We conclude that partisan gerrymandering claims present political questions beyond the reach of the federal courts. "

In another 5-4 vote, the Justices ruled that voters and elected officials should be the arbiters of redistricting issues - rejecting challenges to Republican-drawn congressional districts in North Carolina which included a criterion called "partisan advantage," as well as a Democratic district in Maryland, effectively reversing the outcome of prior rulings in which courts had ordered new maps drawn. Decisions in Michigan, North Carolina and Ohio were similarly affected.