Historical Tillman died in July 1918, so merely carrying him to the Washington conference is not enough for the counterfactual. A politician must remain in office after a settlement to defend it, implement its appropriations, and make its bargains normal. The scenario therefore extends Tillman's life through another election cycle into roughly 1925-26. That limited survival assumption gives his coalition time to preserve the new construction program without granting him an implausibly long additional career.
Notable Point · 37:11-39:50
The alternate-history survival requirement
For Tillman's influence to endure, the scenario must carry him beyond the 1921-22 conference and through another election cycle.