One side is energized by the prospect of the greatest expansion of government support since the New Deal nearly a century ago. The other is fearful about dramatically expanding Washington’s reach at an enormous cost.

They’re all Democrats. Yet each side is taking vastly different approaches to guiding the massive $3.5 trillion spending bill through Congress.

The party is again confronting the competing political priorities between its progressive and moderate wings. The House version of the bill that was drafted this week ushered in a new phase of the debate that could test whether Democrats can match their bold campaign rhetoric on everything from income inequality to climate change with actual legislation.