As Sen. Bernie Sanders recovers from a heart attack at his home in Burlington, Vt., his presidential campaign is pushing ahead without his typical frequent campaign appearances and trying to foster a sense of business as usual.

Surrogates fanned out across the early primary states over the weekend, in some cases replacing Sanders at stops he was not able to make. Sanders supporters also joined striking workers on their picket lines.

And on Monday, the Sanders campaign released a plan to “get corporate money out of politics,” a proposal that would eliminate big-dollar fundraising for all federal elections, enact a constitutional amendment to declare that campaign contributions are not speech, and take aim at the Democratic National Convention.

Fitting with his longstanding efforts to nail down the most left-leaning or purist positions in the party, the changes would undermine the fundraising approach of not only President Trump and the Republicans, but almost all of Sanders’s fellow Democratic candidates, too.

Sanders’s new plan would ban the Democratic National Convention from taking donations from corporations or lobbyists, and it would prohibit national party chairs from future lobbying.

In a statement released with the plan, Sanders cited large corporate donations to the 2016 Democratic convention, saying such companies as Bank of America, Peco Energy, Comcast and Facebook each gave more than $1 million.

“Their lobbyists were everywhere and filled the VIP suites,” Sanders wrote. “This type of corporate sponsorship is a corrupting influence and must end if politicians are going to represent the American people.”

In taking aim at the big-dollar fundraisers utilized by Trump — as well as many of his Democratic rivals — Sanders’s plan reinforces a key point of his pitch: He sells himself as the man most able to garner grass-roots support and stand up to corporate influence.

The plan doubles as a would-be rebuke to those wondering if Sanders’s heart attack would force him from the race. His campaign did not acknowledge that Sanders suffered a heart attack until three days after his emergency procedure in Las Vegas last week to place two stents in a blocked artery.

The campaign has said Sanders, 78, will take part in the next Democratic debate Oct. 15 in Ohio, but has not said if he will return to the campaign trail before then.

Rep. Ro Khanna (D-Calif.), a Sanders campaign co-chair, traveled to Iowa on Friday and Saturday in Sanders’s stead, while another co-chair, Nina Turner, campaigned for Sanders in South Carolina.

For now, policy announcements like the campaign finance plan allow Sanders to stay in the news while he’s still resting at home.

The plan would upend the current system for funding elections, something several of his fellow candidates — including Sen. Elizabeth Warren (D-Mass.) — have also proposed. Sanders has sworn off big-dollar fundraisers and corporate PAC money and relied entirely on small-dollar donations instead.

Before his heart attack grabbed headlines last week, the Sanders campaign was reveling in a $25.3 million fundraising haul for the year’s third quarter, more than any other Democratic candidate raised in a single quarter in this campaign. Warren, who has also sworn off major donors in favor of small-dollar donations, raised $24.6 million.

The rest of the field is continuing to hold major fundraising events, but many of the candidates are raising far less money.

Sanders promises to advocate for legislation that would create mandatory public financing for all federal elections by creating “Universal Small Dollar Vouchers” that would give any voting-age American the ability to “donate” to federal candidates. Andrew Yang has called for a similar plan, which he calls “Democracy Dollars,” to eliminate corporate influence in federal elections.

While Sanders’s plan did not include further details on how the vouchers would be funded, it said the Federal Election Commission would determine the appropriate threshold candidates must meet to qualify for public financing — that is, if the FEC survives a Sanders presidency. His plans aims to “abolish the now-worthless FEC and replace it with the Federal Election Administration, a true law enforcement agency” originally proposed by former Sens. John McCain (R-Ariz.) and Russell Feingold (D-Wis.).

Sanders envisions an FEA made up of three members with legal backgrounds who serve terms long enough to ensure no president could appoint the entire committee at any one time. The FEA would have the power to pursue not only civil penalties but also criminal charges against those violating campaign finance laws.

Many Democratic candidates have criticized the FEC as toothless in the course of the campaign, though Sanders is the only one to call for its complete retooling. Sanders’s plan also attacks corporate influence in politics by banning former members of Congress and senior staffers from future lobbying endeavors.