WASHINGTON — When a House committee sued senior Trump administration officials this past week over their refusal to turn over details of the administration’s failed attempt to add a citizenship question to the 2020 census, it might have seemed a post-mortem to an issue long settled.

But five months after the Supreme Court blocked the question, a steady trickle of new disclosures in the case this past month has sharpened questions about whether Republican Party politics drove the effort to add the question to the head count — and whether the Trump administration tried to conceal that in court.

The disclosures, in a House of Representatives inquiry and a New York lawsuit, bolster existing evidence that a Republican political strategist, Thomas B. Hofeller, played at least an indirect role in crafting a legal rationale for adding the question to the census. They also indicate that a senior Census Bureau official and friend of Mr. Hofeller, Christa Jones, helped draft an explanation of that rationale, apparently for publication had the question been approved.

Those developments could help efforts by critics to definitively pin down how the citizenship question became a Trump administration priority and whether Justice Department officials should be sanctioned for withholding evidence relating to it. Federal judges are hearing demands by the House Oversight and Reform Committee and by plaintiffs in the census lawsuit filed in New York to unseal a trove of census-related documents that the administration has refused to turn over.