The Final Debate Between Tim Ryan and the Trump-Endorsed J. D. Vance Was Relatively Civil Until the Moderator Asked for the Candidates’ Thoughts About the ‘Great Replacement Theory. ’ Ryan Accused Vance of Agreeing with the Controversial Theory, Which Claims Democrats Are Systematically ‘Replacing’ White U. S. Voters with Immigrant Voters, Eliciting a Sharp Retort from J. D.