By Jarrett Renshaw

(Reuters) – The U.S. Democrats plan to reveal a tax strategy Monday. It would aim to collect hundreds of millions of dollars from roughly 700 billionaires in the United States to fund climate change and expand the social safety net.

Faced with opposition from Kyrsten Sinema (one of their senators), Democrats had to adopt the unconventional plan of raising both the corporate and top personal income taxes to fund the massive spending plan. This is an important pillar of Democratic President Joe Biden’s domestic agenda.

The final details are being crafted by the party, and will likely come in between $1.5 trillion to $2 trillion.

Progressive wing members of the party wanted to see a bigger plan. However, opposition from Sinema (and fellow Democratic Senator Joe Manchin) forced the White House into making concessions in order to reduce the cost.

Democrats advocate for higher corporate and income tax rates over the years. They believe that wealthy Americans should be able to pay more for new social benefits. However, their inability to pass such legislation underscores the difficulties the party is facing.

Rich Americans are not required to pay any taxes for their wealth accumulations, including stocks, real estate and art. However, they will be taxed when the asset is sold.

Under the “Billionaire Income Tax” proposal, the federal government would require billionaires to pay taxes on the increased value of assets such as stocks on an annual basis, regardless of whether they sell those assets.

These assets could be subject to annual losses of value.

White House supports the plan.

Janet Yellen, U.S. Treasury Secretary, rejected Sunday’s call for the measure to be a “wealthtax.”

Yellen told CNN that “it’s not a wealth-tax, it’s a tax for unrealized capital gain of extremely wealthy individuals.”

Critics claim that the plan will cause billionaires to move out of stock market valuations, which can be easier than in other markets, and instead into art and real estate.

House of Representatives Speaker Nancy Pelosi claimed that while the plan was appealing, it could only raise $200 billion-250 billion. That means other revenue sources will be needed to help pay for it.

CNN spoke to her about the appeal of the tax on billionaires, however it does not produce as much income.

Pelosi stated that lawmakers can fund the spending bill with a variety of options, even without a corporate tax rate increase. These include better tax enforcement and international taxes harmonization.

Biden Administration officials stated that they believe Congress will pass legislation to establish a global corporate tax minimum agreed upon by 136 nations.