Mark Zuckerberg has frequently found himself sitting before Congress, as lawmakers chastise him for Facebook's flaws and warn him that if he doesn't do his job, they will. Now, as the billionaire founder and his wife, Priscilla Chan, make an unprecedented donation to election infrastructure in the face of Congress' inaction on the multi-billion-dollar shortfall in election funding, the tables have turned.

On Tuesday, the pair announced they are donating $250 million to the Center for Tech and Civic Life, a nonpartisan organization that plans to use the funds to help state and local governments pay for things like hiring and training poll workers, renting polling places, buying protective gear for poll workers, purchasing equipment to process mail-in ballots, and voter education. The couple is also giving $50 million to the Center for Election Innovation and Research, which will fund outreach to inform voters about registration, mail-in voting, and other peculiarities of carrying out an election in a pandemic.

The $300 million outlay is almost as much as the $400 million Congress itself set aside in March as part of the $2 trillion CARES Act. Since then, though, Congress has failed to allocate any additional funding to help state and local officials adapt, despite reports suggesting Congress would need to spend $4 billion to truly meet the scale of the need. And yet, in mid-August, Congress adjourned without allocating any additional money for elections, leaving election officials and experts desperate to find new funding — even if that means taking it from the guy whose company stands perpetually accused of stoking chaos and confusion around elections.

"It is truly a shame that we need to rely on private donations in order to support the basic needs of our democracy, but if Congress is unwilling to step up, we need to find money wherever we can find it," said Nate Persily, a Stanford law professor and co-founder of the The Stanford-MIT Healthy Elections Project, which aims to help state and local officials safeguard the 2020 election.

"Ordinarily I would not want to look to the private sector to meet the basic budget for the infrastructure of our democracy, but we're at an extraordinary point here," said Wendy Weiser, director of the Brennan Center's Democracy program, which has produced multiple reports on the scope of the election funding gap this year. "We cannot let Congress' failure be a failure for democracy."

In a statement, Zuckerberg and Chan said the donations will "help provide local and state officials across the country with resources, training and infrastructure necessary to ensure that every voter who intends to cast a ballot is able to, and ultimately, to preserve the integrity of our elections."

But what can $300 million really buy between now and November? A whole lot and not enough.

Consider what it will take to handle the dramatic increase in mail-in voting that is likely to take place this year. Just one ballot drop box can cost as much as $10,000 to purchase and install. According to the Brennan Center's nationwide estimates, getting fully equipped for mail-in voting would cost $982 million to $1.4 billion. That includes the cost of printing ballots (at least $54 million), mailing them (at least $413 million), purchasing nearly 12,000 ballot drop boxes that would be needed to meet the estimated demand (at least $82 million), ballot tracking software ($4.2 million) and more.

In Pennsylvania alone, the Brennan Center estimates local officials would need at least $36.3 million just to cover the cost of mailing, processing and tabulating mail-in ballots. The technology governments are buying to do this work is mission critical, Persily explained. "Even if you're just talking about opening the envelopes, that could take a week for human beings to open a million mail ballots," he said. "You need to automate the process."

And yet, in many states, Weiser said even if local governments get the funding for these machines now, it's already too late for them to go through the procurement process to buy them, let alone to have them manufactured, installed and tested before Election Day. That means whatever funding comes through between now and November will predominantly be spent on personnel.

"That doesn't mean there's less of a need, there's just much greater labor costs," Weiser said, noting that governments will have to prepare for higher than usual no-show rates, as poll workers in high-risk groups opt to stay home on Election Day.

The cost of labor was already expected to be sizable, even before it became clear that states wouldn't be able to procure the equipment they need. In April, the Brennan Center estimated that simply maintaining in-person voting could cost $271.4 million nationwide.

All of which is to say that Zuckerberg and Chan's commitment can certainly make a dent, but it hardly lets Congress off the hook. It seems unlikely the donation will give Facebook much cover from its critics, either. Lately, the company has touted its efforts to register 4 million voters and surface reliable information about the election through its newly created Voting Information Center. But it's been unyielding on some of its most controversial policies, including refusing to fact-check politicians' speech and declining to take action against one of President Trump's posts that appeared to encourage violence.

Now, some watchdog groups say Zuckerberg and Chan's financial contribution is little more than a public relations maneuver to cover up for Facebook's misdeeds.

"Needless to say, this is a significant financial commitment to help state and local officials administer safe and secure elections amid unprecedented challenges, and we applaud that investment," Nicole Gill, director of the group Accountable Tech, which pushes social media companies on issues related to democracy, said in a statement. "But let's be clear: There's not enough money in the world to paper over the damage Facebook has done to democracy."

Still, Persily and Weiser said that whatever Zuckerberg and Chan's motivation may be, in the absence of leadership from Congress this funding is one of the only safeguards we currently have against a calamitous Election Day. "This is not the ideal situation," Persily said, "but if the alternative is that we have an election meltdown, I think we should take the money."