House Oversight and Government Reform Committee Chairman Darrell Issa (R-Calif.) said Friday he would give the White House one more chance to allow a top official to testify.

But Issa warned if the White House doesn’t take this chance, he is ready to enforce a subpoena that the Obama administration has so far ignored.

House Oversight and Government Reform Committee Chairman Rep. Darrell Issa, R-Calif., is giving a top White House official one last chance to appear before his committee. (AP Photo/Manuel Balce Ceneta)

“Mr. Simas’ failure to appear, despite having been compelled to do so by a lawfully issued subpoena, was contumacious, and the committee is prepared to enforce its subpoena,” Issa wrote.

Issa issued a subpoena to hear testimony from David Simas, the director of the White House Office of Political Strategy and Outreach, on the issue of whether that office violates a federal law prohibiting political activities by the government. But the White House warned last week that Simas would not testify because he is “immune.”

Issa’s letter argued that prior court cases say Simas is not immune.

“The Court made absolutely clear that senior presidential advisors ‘do not have absolute immunity from compelled congressional process,’ and it went on to say that subpoenaed advisors are legally required to appear and testify in response to a congressional committee’s subpoena, although they remain free to invoke legitimate testimonial privileges in response to specific questions,” Issa wrote.

Issa noted that Simas is the first witness under subpoena who has failed to show up to testify.

Read Issa’s letter here: