Of course, it's important to remember that these new taxes are simply what Biden proposed. “He was elected president, not dictator,” Levine said. “Accordingly, Congress will still have the biggest say in what will happen.”
The chances of any of Biden's agenda making it through Congress are at best unclear. Tuesday's results still leave Democrats well short of the 60-vote supermajority needed for cloture, a vote to end Senate debate on most legislation, though spending and revenue bills could pass with a 51-vote simple majority via the process of reconciliation.
Senate Republicans could still postpone the passage of any taxation or spending legislation by proposing a never-ending series of amendments to the bills, a technique sometimes referred to as vote-a-rama. Congressional Democrats are also well short of the 67-vote supermajority needed to amend the constitution or overturn a veto.
While Biden and his staff have influence over how tax legislation will be shaped, Biden doesn't have to worry about running again in two years. House Democrats will. Biden also has vested interest in ensuring Democrats don’t lose any seats, given how closely split Congress is.
Even when passing bills with a simple majority, he won't be able to lose a single Democrat vote in the Senate, which means every Democrat has to be on board with the legislation unless a few Republicans can be persuaded to join the opposition. Purple-state Democrats will almost certainly balk at ultra-progressive changes.
So what's likely to happen? "It's a fool's game to try and handicap [Washington D.C.], but if I have to guess, I'd say the most likely outcome is that Dems ultimately roll back a lot of the changes made by the TCJA,” Levine predicted.
“Doing so, but not going further, gives them a lot of political cover. Suddenly, it's not really raising taxes. It's just returning them to their previous levels. So things like returning the top rate to 39.6% seems reasonable ... though perhaps at a different income threshold than proposed,” Levine said.
When can we expect these changes? With a Democratic majority, the Biden administration can legislate these changes this year, although some provisions may be phased out over a number of years, experts said.