To be clear, Constitutionally the United States Senate only needs a majority to pass a law that changes the Taxes collected from corporations.
The Senate Filibuster which requires a 60-vote majority is not a Constitutional provision, and you wouldn't strictly need a Treaty for this agreement, if all the countries simply adopted the same tax provisions.
So, if the Democrats had the vote for it, they could pass this law with 0 Republican votes. In fact, since raising taxes is a budgetary measure, they could absolutely pass the corporate tax increase on reconciliation and do it with 0 Republican votes and without touching the filibuster. So, it seems quite plausible to me that this will happen.
The Senate Filibuster which requires a 60-vote majority is not a Constitutional provision, and you wouldn't strictly need a Treaty for this agreement, if all the countries simply adopted the same tax provisions.
So, if the Democrats had the vote for it, they could pass this law with 0 Republican votes. In fact, since raising taxes is a budgetary measure, they could absolutely pass the corporate tax increase on reconciliation and do it with 0 Republican votes and without touching the filibuster. So, it seems quite plausible to me that this will happen.