Michael Wines and Emily Bazelon for the NYT:

Census Bureau experts have uncovered serious flaws in a section of the 2020 head count that potentially affect the enumeration of millions, according to people familiar with the census operations, delaying still further the completion of state-by-state population totals that the White House has demanded before President Trump leaves office next month.

Census experts told the Trump administration last month that data-processing delays were making it impossible to meet that schedule, but the agency’s political appointees have continued to press for shortcuts in an attempt to deliver on the White House’s demand. On Friday, people involved with the census but not authorized to make official comments said the latest delay — adding 10 to 14 more days to a process that was already set to end well beyond the Dec. 31 statutory deadline — appeared to doom that last-ditch rush.

The extent of the additional problems — relating to the count of residents of group quarters like prisons, college dormitories or homeless shelters — effectively means that “that isn’t going to happen,” one official, who declined to be named for fear of retribution, said of meeting the deadline.

The Trump administration needs the bureau’s state-by-state population totals if it is to fulfill the president’s plan to strip undocumented immigrants from the state counts used to reapportion the House of Representatives. Such a move, unprecedented in American history, would produce an older, whiter, more rural population base for reallocating House seats that would mostly benefit Republicans, analysts say.

Many experts see the bureau facing deadlines it cannot possibly meet while maintaining its standards. Some bureau officials remain concerned that Mr. Trump will demand numbers anyway, a move that could plunge the nation into uncharted legal territory if the Democratic House and the new Biden administration reject the results.