Governments threatened with the debt ceiling should not hesitate to
use questionable maneuvers to keep the government operating — and
they should not try to go to court to argue for them. Biden should do
what is needed, then let the Republicans sue if they wish.
If government lawyers were to argue in the Supreme Court, in advance,
that the maneuver id lawful, the current right-wing politicized court
would have every motive to rule "it is unlawful", and thus strengthen
the Republican hostage-takers.
However, if Republicans file that case after the maneuver is used,
then a ruling of "it is unlawful" would mean instantaneous default.
Even the right-wing justices would hesitate to do that. They would
have to find a way to avoid that.