Enlarge / Ronald Rotunda prepares to deliver testimony.

As Chair of the House Committee on Science, Space, and Technology, Rep. Lamar Smith (R-Texas) has sent a lot of subpoenas. It started with his campaign to dig up wrongdoing by NOAA climate scientists after they published a paper updating the agency’s global temperature dataset—an update that happened to weaken Smith’s claim that the world hadn’t warmed in some number of years. When NOAA refused to start handing out the researchers’ e-mails and drafts, Rep. Smith started firing off subpoenas.

More recently, subpoenas went out to several state attorneys general who have launched securities fraud investigations of ExxonMobil. The investigations followed media reports that the company had funded its own climate research in the 1970s and ’80s—and that research made it clear that climate change was real and dangerous. After ExxonMobil shut down the research, it focused on fighting any climate policies by claiming that climate change was uncertain. The company never publicly disclosed the potential risks to its business, as regulations require.

Rep. Smith’s subpoenas targeted both the attorneys general pursuing the investigation and a pile of environmental groups that advocated for the investigation. That’s how we got to yesterday’s House Science Committee hearing, entitled “Affirming Congress’ Constitutional Oversight Responsibilities: Subpoena Authority and Recourse for Failure to Comply with Lawfully Issued Subpoenas.” In essence, Smith was seeking legal backing for his actions.