Yet senators on the Budget Committee viewed Sanders as taking an extreme position precisely so that it would yield a compromise all the more fruitful for liberal Democrats. If Sanders had started off endorsing Biden’s number of $4 trillion, it’s possible he and other progressives might have had to settle for a number lower than the $3.5 trillion they agreed upon. “Bernie Sanders is like a human embodiment of shifting the Overton Window,” said Sen. Tim Kaine (D-Va.), who serves on the Budget Committee. “We wouldn’t be there without him putting out $6 trillion.” With a ceiling of $3.5 trillion, Sanders says he can pursue all the changes that he’s prioritized, just not for not as long as he wants. That raises the possibility of future fights over the extension of programs like the expanded child tax credits championed by Democrats.