In a letter Monday, Rep. Elijah Cummings, D-Md., accused Oversight Committee Chairman Darrell Issa, R-Calif., of making "unfounded accusations" against Todd Park, the administration's chief technology officer, the Hill reported.
"The evidence before our committee demonstrates that Mr. Park is an honest and exemplary public servant, and your unsubstantiated public attacks against his integrity are a deficient basis on which to justify a subpoena against him," Cummings wrote in a letter also signed by Rep. Gerald Connolly, D-Va.
Cummings said Issa's subpoena diverted Park's focus on his work and could "seriously impair" the race to repair healthcare.gov, which launched miserably Oct. 1 but administration officials promised would operate more smoothly by the end of November.
"Rather than denigrate Mr. Park's reputation and impede his time-sensitive work, we request that the committee accept his reasonable offer to testify before the committee in December," the letter said.
Issa subpoenaed Park last week to testify Wednesday, saying Park's "long history of involvement in the development and rollout of Healthcare.gov" meant his testimony before the committee was crucial, the Hill said.
Issa said his effort to get Park before the committee several times was rebuffed by the White House, who said Park was too busy -- resulting in the subpoena.
Cummings on Monday accused Issa of selectively leaking and misrepresenting internal documents to make political hay.
Issa last week accused Park of "engaging in a pattern of interference and false statements," saying he had misrepresented website test results that showed how much capacity the site could handle ahead of its launch.
Cummings responded that the oversight committee had "absolutely no evidence" that Park interfered in the investigation "and we certainly have identified no evidence that Mr. Park made any 'false statements' relating to healthcare.gov or any other matter."