2020 Democratic presidential candidate Sen. Elizabeth Warren (D-MA) speaks during a rally in Washington Square Park on September 16, 2019 in New York City.Drew Angerer | Getty ImagesSen. Elizabeth Warren on Wednesday unveiled a plan that takes aim yet again at the multibillion-dollar lobbying industry. This time, she’s looking to hit them where it could hurt the most: their wallets.Warren’s latest proposal is calling for an “excessive lobbying tax,” which would require lobbying shops to pay a tax if they spend over $500,000 per year on influence campaigns.The proposed tax marks the latest round in a battle with an industry that, in part, helped fund her campaigns for Senate during the 2012 and 2018 election cycles.Throughout those contests, Warren accepted at least $95,000 from various lobbyists and later transferred $10.4 million from her Senate campaign coffers to her 2020 organization. However, she was one of the first Democratic primary candidates to say she would not accept donations from lobbyists.”Under my lobbying tax proposal, companies that spend between $500,000 and $1 million per year on lobbying, calculated on a quarterly basis, will pay a 35% tax on those expenditures,” Warren said. “For every dollar above $1 million spent on lobbying, the rate will increase to 60% — and for every dollar above $5 million, it will increase to 75%.”She said that if her tax hit the lobbying organizations of the U.S. Chamber of Commerce, Koch Industries, Pfizer, Boeing, along with many others, then over the past 10 years it would have brought in over $10 billion in total revenue.The proceeds from this tax, Warren says, would go into what she defines as a new “Lobbying Defense Trust Fund.” The money in that fund will be used to insulate various congressional and federal agencies from lobbyists trying to influence their decision-making.”Every time a company above the $500,000 threshold spends money lobbying against a rule from a federal agency, the taxes on that spending will go directly to the agency to help it fight back,” Warren said.Previously, Warren called for banning lobbyists from contributing or fundraising in any capacity for their preferred political candidates.