The reference is possibly to the Green New Deal or to Build Back Better. Both probably qualify as "multi-trillion social programs", but perhaps the former fits the description better.
> social aims like job creation and reducing economic inequality
> the plan could cost between $51–$93 trillion over the next decade
https://en.wikipedia.org/wiki/Build_Back_Better_Plan
> the largest nationwide public investments in social
> a variety of social policy initiatives
> $1.9 trillion
> $2.3 trillion (which, when combined with the American Families Plan, amounted to $4 trillion in infrastructure spending)
> $3.5 trillion reconciliation bill
> Democrats could advocate multi-trillion social programs