President-elect Donald J. Trump announced on Tuesday that his nominee to lead the C.I.A. would be John Ratcliffe, a former Texas congressman who served as the director of national intelligence during Mr. Trump’s first term.

Mr. Trump called Mr. Ratcliffe a “warrior for Truth and Honesty with the American Public” on his social media account. As the national intelligence director, Mr. Ratcliffe served as the president’s chief adviser on intelligence issues.

As a congressman, Mr. Ratcliffe fought on Mr. Trump’s behalf, helping to pursue investigations into Hunter Biden, the president’s son, and repeatedly criticizing the investigations into ties between Russia and Mr. Trump’s 2016 campaign.