Republicans hold a slim majority in the upper chamber, with 53 senators to the 47 who caucus with the Democrats. If all Democratic senators vote against the bill, as is expected, it will take only a handful of GOP rebels to defeat it.

Senate Republicans have offered warnings that President Donald Trump may need to adopt a softer approach than his usual strong-arm politics to pass his tax and spending bill in the upper chamber. Public barrages by Trump and his top aides against Senate GOP holdouts are complicating efforts to muscle through the House-passed measure that advances

CNN chief data analyst Harry Enten reports that Elon Musk's reach on social media is more influential than the money he can spend campaigning for or against Republicans. KATE BOLDUAN, CNN HOST: And after spending -- what was it -- $290 million to help President Trump and his allies get elected in 2024.

As their fight over the tax bill explodes into view, some lawmakers hold out hope for a reconciliation after the painful divorce.

Analysis: GOP lawmakers and operatives said Republicans should be scared of getting crosswise with either Trump or Elon Musk — a tough task when they are fighting each other.