In 1992, current House Majority Leader Steny Hoyer (D-Md.) spoke in favor of indexing capital gains to inflation. 

Hoyer said: “The capital gains provisions in H.R. 4287 benefit small business by indexing newly purchased assets. Income gauged would be much more reliable so that, real not inflationary gains will be taxed, and taxed at the same 28 percent maximum rate on gains.”

Other Democrats like Chuck Schumer lined up on the House floor to praise H.Amdt. 438, an amendment to the H.R. 4210, the Tax Fairness and Economic Growth Act of 1992. The amendment would have ended the inflation tax on capital gains. 

Ultimately, 220 House Democrats voted to end the tax on inflation, including Hoyer, Schumer, Nancy Pelosi, and Bernie Sanders. Read Democrat remarks in support of indexing capital gains to inflation here

As President Trump prepares to index capital gains taxes to inflation, ATR expects strong support from the Democrat party based on their previous statements and votes. 

See also: 

Schumer Video: “I Would be for Indexing All Capital Gains”

The tax law Chuck Schumer hates – but used to praise
The Case for Ending the Inflation Tax on Capital Gains
Indexing Capital Gains Taxes to Inflation Resources