Joe Biden

The outline of the tax and spending bill provided a breakthrough after a long standoff between moderate senators and progressive Democrats.

A new round of haggling started, as they worked to fill in details and deal with last-minute attempts to restore priorities that had been left out.

Potential new provisions could create a seismic shift in tax.

Some House lawmakers raised doubts about the terms of the deal and whether differences could be resolved in the next few days.

Hikes in the top tax rates are off the table, although a “billionaire’s tax” on unrealized capital gains is under discussion.

There is increased momentum for an income tax on $1 billion or more in annual income, or three consecutive years of $100 million or more in income.

President Joe Biden’s acknowledgement that he doesn’t have sufficient Senate Democratic backing for his proposed increase in the U.S. corporate tax rate gives fresh impetus to efforts by negotiators to find alternative revenue sources for a sweeping social-spending bill.

Democratic negotiators have been working to address opposition from Senator Kyrsten Sinema, an Arizona moderate, to boosting rates.

The Democratic Senator said there’s little chance that Congress can complete work on President Biden’s economic agenda by the end of the month.

The president has warned progressives that they will have to temper expectations for the final legislation.