With a week to go before the midterms , a group of Democratic senators are demanding that Mehmet Oz , the administrator for the Centers for Medicare and Medicaid Services (CMS), share communications his department may have had with far-right groups promoting a baseless conspiracy theory about left-wing groups stealing votes from residents of nursing homes.

In July, Oz’s agency issued a memo rescinding previous guidance on how staff at nursing homes could help residents to vote by assisting with mail-in voting or transporting residents to polling locations. The memo replaced that guidance with threats of prosecution if staff “engage in inappropriate coercion or other violations of residents’ rights.” Referring to this memo, election denial groups last month began to boost claims that voter fraud was happening inside care facilities.

That campaign was spearheaded by the Election Integrity Network, a group led by Cleta Mitchell, a former adviser to president Donald Trump.…