The appearance provides Mr. Smith with what is likely to be his best opportunity to challenge President Trump’s assertion that he was persecuted for his politics, not for his misdeeds.
As the F.B.I. has added payback to its portfolio, Republican lawmakers like Senator Charles E. Grassley have emerged as a clearinghouse for leaks and whistle-blowers.
Under Kash Patel, F.B.I. personnel have worked to paint a damning, one-sided narrative intended to discredit and embarrass federal law enforcement officials who investigated Donald J. Trump and his allies.