Ken Block

Voting booths had been closed for less than 24 hours four years ago when Ken Block’s phone rang. On the other end was a lawyer from the Donald Trump campaign in need of a data pro who could help suss out voter fraud, possibly enough to keep the President in the White House for a second term. Block, who had spent the seven years leading up to that Nov. 4, 2020, phone call investigating voter fraud, was candid with Alex Cannon: it was going to be really tough, if not impossible, to help Trump’s lawyers find sufficient voter fraud that would stand up in court. After all, voter fraud before 2020 had rightly been treated as a miniscule misdeed and never enough to make a lick of difference in the outcome.

After a diligent search, Block told the campaign that the same trend had held during the election that had just ended, despite Trump’s baseless claims of widespread fraud and corruption. “I would instantly do this work again because the assessment of what happened in an election is a black-and-white exercise. Either there was fraud or there was not fraud,” Block tells TIME. “And you should be able to quantify exactly how much fraud there was, and you should be able to explain it.” Block, a former Republican candidate for Rhode Island governor, could do neither.

In the years since, Block has become perhaps the most effective truth-squadder against persistent Republican claims about the Big Lie. This year, he even refuted those arguments point by point in a highly detailed book, Disproven. More crucial to the 2024 elections, he also explored the vulnerabilities that remain. “The threat comes from within,” Block says. “What I’m most worried about in this election cycle is the role that partisan election officials might play in altering the outcome of an election.”