Seeing the federal government slip into Republican hands is terrifying campaign finance experts, who are bracing for a wave of deregulation that could give millionaires and billionaires powerful new ways to influence American politics.

Top Republican leaders — most vocally, Senate Majority Leader Mitch McConnell — have spent years advocating specific changes that would gut what’s left of an American campaign finance regime that’s already been crippled.

"We’re getting ready for a fight. We know that Republicans aren’t going to do anything about Citizens United and that they’re probably going to want to throw out what little is left of McCain-Feingold," says Craig Holman, a government affairs lobbyist at the transparency nonprofit Public Citizen, referencing the bipartisan bill from 2002 that put some restrictions on campaign spending. (Many of the restrictions put in place by that bill were thrown out by the Supreme Court’s Citizens United decision in 2010.) "It's going to be a tough battle.”

With control of the House and Senate, congressional Republicans have the power to ram through a series of measures — including repealing limits on what political parties can get from individual donors — that are inscribed in the GOP’s official party platform.

The big problem in trying to game out what will happen is, as it is across multiple policy questions, the inscrutability of what Donald Trump really wants. Trump ran on an anti-corruption message by promising to throw the moneyed special interests out of government and free Washington from the grip of the “political establishment.”

But early moves by his transition team suggest he’s eager to staff his administration with lobbyists. He’s also notoriously inattentive to policy details — including around campaign finance reform. So it seems entirely possible that Trump will jettison his pledge to eradicate money’s grip on politics and instead allow congressional Republicans to strengthen it.

Letting billionaires directly bankroll entire political campaigns

There is really not all that much left to prevent big money from influencing American politics. Donors can already spend as much as they want on “independent” Super PACs that take out millions in political advertisements. Corporations can give as much as they want to these Super PACs, and they’re finding ways to do so entirely in secret.

But weakened though the current campaign finance regime might be, it hasn’t been totally toppled. Vital bulwarks really do remain that prevent politicians from engaging in some kinds of fundraising — at least for the time being.

The Republican Party platform has an array of plans for getting rid of those last bulwarks. One of the most extreme money-in-politics proposals that Republicans have considered would roll back or eliminate the limits on what individual donors can give directly to candidates. Here’s reporter Kate Ackley writing at Roll Call Monday about the key priorities for some Republicans around campaign finance (emphasis added):

(Hans A.) Von Spakovsky, who manages the Election Law Reform Initiative at the conservative Heritage Foundation, says he’s hopeful that McConnell and Trump, along with a Republican House, will greatly increase the limits on donations to party committees and candidates, or undo the limits altogether. Individual donors can give no more than $2,700 directly to candidates per election in the 2016 cycle.

On first read, this idea to “undo the limits” of private donations to candidates may sound like a technical policy proposal or a tweak to an existing program.

It’s not. This would be a really, really big change. Currently, if billionaire casino magnate Sheldon Adelson wants to donate to Florida Sen. Marco Rubio’s 2020 presidential run, he can do so in one of two ways: (1) He can give to Rubio’s campaign directly, but only up to $2,700; and (2) He can also give as much as he wants if he only gives to an outside group, like a Super PAC, that’s legally bound to avoid coordination with the candidate.

In the context of a presidential or even a Senate campaign, $2,700 really isn’t a lot of money. Most of these races cost tens of millions of dollars, if not more. And that means politicians who want to build strong fundraising apparatuses have to go to tons of different people to make each $2,700 gift add up.

The plan pushed by Republicans would essentially throw that restriction out the window, according to Bob Biersack, a senior fellow at the Center for Responsive Politics who spent nearly 30 years working for the Federal Election Commission. Getting rid of that spending limit would give a billionaire the ability to fully bankroll entire presidential or Senate campaigns, Biersack said. Instead of having to ask hundreds or thousands of people for the maximum $2,700 gift, a politician could go to just one person who is rich enough to fund his or her entire campaign.

To be clear: We don’t know for certain if congressional Republicans will go for this. Michael Malbin, executive director of the Campaign Finance Institute, tells me he thinks it’s unlikely, though not impossible, that Republicans will push for this aggressive of a measure. Holman was more bullish, telling me he expects it’s likely the GOP does try to push this measure through given McConnell’s record on money-in-politics.)

All the experts I interviewed expressed serious alarm over the idea.

“It’s obvious to me that we do not want a system where members of Congress can be completely funded by a handful of individuals who also have institutional interests before Congress,” Biersack said. “I don’t think we want to have candidates for elected office in that position.”

“Legalized extortion” could come back to Washington

An outright repeal of limits on individual donations to candidates is the nuclear option that could deal a huge blow to campaign finance regulations.

But there are several other ideas Republicans want that would dramatically expand the ability of the megawealthy to exert influence over the political process, according to Malbin and Holman.

For instance, they said, McConnell has long had his eye on easing or erasing the limitations on what individuals can give to the political parties.

Currently, a donor can give around $600,000 per election cycle to the Republican or Democratic Party. If that number were raised or even eliminated — as the GOP’s official platform demands — some millionaires could and almost certainly would take advantage of the opportunity to spend even more, according to Malbin.

Some experts think this wouldn’t necessarily be all bad. It might, as some progressive groups have argued, help make sure money that may otherwise flow to unaccountable “dark money” organizations would instead be managed through the institutional channels of the official party organs. And it could help reduce the pressure on candidates to go directly to donors, since they could instead rely on their state or national parties to raise campaign donations.

But the idea is still rife with possibilities for corruption. It would essentially allow party leadership to ask corporations or individual donors for gobs of cash even as they considered legislation directly relevant to those groups. Before it was curbed in 2002, business leaders like the CEO of Deloitte complained this kind of arrangement gave politicians carte blanche for “legalized extortion.”

“We don’t have to guess at hypotheticals for what would happen if they brought this back,” Malbin says. “It would be everyone going back to extorting corporations. As a party, you’d be irresponsible for not doing it.”

Shredding the last vestiges of McCain-Feingold

In 2002, in the wake of several high-profile corruption scandals involving Enron and other large corporations, Congress passed a bipartisan bill called McCain-Feingold that outlawed several forms of limitless political donations.

Most of that bill was shredded by the Supreme Court, which ruled the federal government’s attempts to rein in spending amounted to an abridgment of free speech.

But while most of McCain-Feingold is dead, a part of it remains — the section of the law that contains rules forcing corporations and donors to make some of their political spending public, according to Holman. These disclosure rules have largely held up in court, despite conservative-led lawsuits aimed at striking them down.

“The only thing left on the books are a fairly weak disclosure system — and the Republicans will probably try to end that, too,” Holman says.

If Feingold-McCain’s remaining disclosure rules are repealed, the whole premise of campaign finance restrictions in America will become something of a joke, according to Holman.

“There would be no need for a Federal Elections Commission, so they may dismantle that as well,” Holman says. “If they get rid of the rest of Feingold-McCain, all we’d have on the books is what Citizens United recognized — that outright bribery should still be illegal.”

Other ways the GOP can gut the remaining campaign finance laws

There are still others ways in which the Republican Party has committed itself to shredding the remaining barriers to political spending.

One example is a “policy rider” McConnell has long pushed to prevent the Securities and Exchange Commission from crafting new rules for corporate political spending disclosure. (That may not matter if Trump appoints an SEC commissioner who simply doesn’t care much about enforcing money-in-politics regulations.)

Another is that it’s currently illegal for nonprofits to endorse political candidates under the IRS tax code. The Republican platform calls for the abolishment of that restriction, according to the Huffington Post, and so it’s possible to imagine the Republicans would seek to do away with the requirement.

Beyond that, House Republicans may revive another measure to allow nonprofits to donate whatever they want to campaigns without disclosing it to the government.

In April 2016, the House Republicans passed a bill called the Protecting Children and Taxpayer Identity Act. As House Democrats pointed out at the time, it would have allowed a drug cartel or a foreign government to spend unlimited money on funding campaign ads — without having to tell the IRS, according to Josh Stewart, who tracks money-in-politics issues at the Sunlight Foundation.

“This is a huge check on illicit and illegal money being moved through nonprofits to be spent on elections,” Stewart says. “And the Republican Congress has wanted to do away with it.”

But big campaign spending didn’t win the 2016 election, so why do we care?

Hillary Clinton outraised and outspent Donald Trump by tens of millions of dollars and still lost. Bernie Sanders outspent Hillary Clinton and lost the Democratic primary. Jeb Bush spent more than anyone and barely broke a few percentage points. In the case of Sanders, and to a lesser extent Trump, grassroots fundraising seemed up to the task to match or even outperform billionaires’ ability to spend on the political process.

But as I’ve noted, many political scientists think one of the reasons Trump and Sanders did so well this year, contrary to all expectations, is that they were able to capitalize on the widespread perception that corrupt forces and special interests had destroyed the public’s ability to have their voices heard in Washington.

Whether that’s true or not, the candidates who would otherwise have been considered outside the political mainstream — because of a lack of experience or a string of policy proposals — did better because of it. And if the Republicans only force that problem of corruption to deepen, what will the 2020 primaries look like? What kind of advantage could those outside of an even more corrupt-seeming system accrue to their benefit?

And that’s leaving those who think our system is already corrupt to fear what the congressional GOP will send to his desk.

“It’s easy to pour anonymous money into the system, and [House Speaker Paul] Ryan and McConnell have repeatedly supported doing so,” Stewart says. “It’s very concerning for those who care not only about transparency but limiting the voice that special interest groups have. The GOP Congress has a record here we should worry about.”