Should Marty Makary take the reins at the FDA, transitioning from gadfly to the head of an agency that regulates a fifth of the U.S. economy, he would have to engage in the thorny challenges of governing.

Senators asked Makary about the FDA’s decision to cancel a scheduled meeting of its outside committee of vaccine experts to discuss the design of this year’s influenza vaccine

Marty Makary, Trump’s pick for FDA commissioner, testified before the Senate health committee Thursday.