Bernie Sanders swipes at Manchin for nixing Biden's billionaire tax plan, saying 'I don't care' what he has to say

• Sanders swiped at Manchin for torpedoing Biden's billionaire tax plan.
• "I don't care what Mr. Manchin has to say," he told Insider.
• It was the second time in five months that the conservative West Virginia Democrat sunk a billionaire tax plan. 

Sen. Bernie Sanders took a swipe at Sen. Joe Manchin of West Virginia on Tuesday after the conservative Democrat sunk a fresh White House tax proposal taking aim at the richest Americans.

"I don't care what Mr. Manchin has to say," he told Insider on Tuesday.

He went on: "At a time of massive income and wealth inequality where billionaires are doing phenomenally well and in some cases don't pay any federal taxes, it's absolutely essential that we have a progressive tax system and demand billionaires pay their fair share in taxes. We got to go forward on that."

Manchin came out in opposition to President Joe Biden's tax proposal less than 12 hours after it was formally unveiled. It's the second time in five months that he derailed a specific proposal designed to target the super-rich. Democrats are closer to reviving pieces of their defunct social and climate bill, but it can reach Biden's desk only if all 50 Senate Democrats cast a vote for it.

The plan would establish a 20% minimum tax rate on households worth $100 million or more and would expand the definition of taxable income to include the accruing value of unsold investments like stocks or bonds, otherwise known as unrealized capital gains. Currently, gains on investments are taxed only when they're sold for cash.

The conservative Democrat is against taxing these financial investments annually. "You can't tax something that's not earned — earned income is what we're based on," he told reporters on Tuesday. "Unrealized gains is not the way to do it."

Manchin and Sanders have had an icy relationship in recent months. The Vermont independent has repeatedly criticized Manchin for derailing Biden's economic agenda late last year.

He opened the door to backing a primary challenger to Manchin in 2024. Sanders also swiped at Manchin for siding with the GOP and allowing the expiration of the expanded child tax credit.

Manchin has taken Sanders to task as well, saying his ideology is "not what I think the majority of Americans represent."