FILE PHOTO: Democratic 2020 U.S. presidential candidate and U.S. Senator Elizabeth Warren (D-MA) speaks at a campaign stop in Hollis, New Hampshire, U.S., September 27, 2019. REUTERS/Brian Snyder/File Photo

LAS VEGAS (Reuters) - Democratic presidential hopeful Elizabeth Warren on Wednesday proposed taxing any corporation or organization that spends more than $500,000 annually in lobbying the federal government, expanding on her plan she has said would “end lobbying as we know it.”

Warren, a U.S. senator from Massachusetts, has centered her campaign on rooting out corruption in Washington. She has steadily risen in opinion polling this year, challenging fellow liberal U.S. Senator Bernie Sanders for the No. 2 spot behind former Vice President Joe Biden.

She previously said she would impose an excessive lobbying tax as part of a broader anti-corruption plan that would also bar most federal officials for life from serving as lobbyists, prevent lobbyists from donating to candidates and outlawing lobbying on behalf of foreign entities.

On Wednesday, she outlined the details of the tax, which would impose a 35% rate on lobbying spending between $500,000 and $1 million, 60% between $1 million and $5 million, and 75% on all spending in excess of $5 million.

If such a tax scheme had been in place over the past decade, it would have affected more than 1,600 organizations, raising $10 billion, according to the campaign.

Warren said she would use the revenue from the tax to establish a “lobbying defense trust fund” to help congressional agencies push back against corporate influence and an Office of the Public Advocate to elevate the viewpoints of working Americans when agencies are writing new regulations.

“Corporate lobbyists are experts at killing widely popular policies behind closed doors,” Warren wrote in announcing the proposal.