In the summer of 2006, I jumped into the ring for a few rounds of debate with Robert F. Kennedy Jr., who was peddling reckless claims about an important issue on which he lacked expertise. It wasn’t vaccines. It was the 2004 presidential race. In an article for Rolling Stone, Kennedy suggested that the election had been stolen from John Kerry — a suggestion that, after thorough reporting, didn’t hold up.But now I see where I went wrong. Not on the merits; there’s still no case that Kerry actually won in 2004. My mistake was attempting to debate and debunk Kennedy in the first place. At best, the effort was a waste of time and energy; at worst, a big bow-wrapped gift of the thing a conspiracy theorist desires most — recognition that his arguments are important enough to merit serious debate.After getting in the mud with Kennedy all those years ago, I realized something important that we’d do well to remember now, as Kennedy mounts a long-shot run against Joe Biden for the Democratic presidential nomination: You can come armed with all the facts in the world, but when you’re dealing with a conspiracist, there’s no real way to “win” an argument. For people whose views aren’t anchored to facts, winning is simply getting attention — and when you publicly argue with someone like Kennedy, you’ve already lost.I got to thinking about all of this last week, when Kennedy went on Joe Rogan’s podcast and served up a helping of misinformation on the issue for which he is best known, his conviction that several common, widely-used vaccines are harmful.When Peter Hotez, a well-known vaccine researcher, tweeted a link to a Vice story critical of Rogan’s anti-vaccine statements and Kennedy’s appearance on the show, Rogan offered a $100,000 charitable donation if Hotez would come on the podcast to debate Kennedy. Not long after, Elon Musk chimed in, and soon an avalanche of Twitterati were pledging money for a debate; according to one Twitter user who claims to have been tracking the pledges, the pot is now over $2 million.So far, Hotez has courageously refused to take the bait, rejecting, as a physician and scientist, an effort to goad him into defending his work from a skeptic who has for years resisted evidence on vaccines. A back-and-forth between Kennedy and Hotez or another vaccine expert wouldn’t prove anything. And that’s not scientists’ method, anyway. They have established ways of assessing empirical questions — you know, things like lab experiments and clinical trials — and none of them involve owning an interlocutor on a popular podcast.And what would winning a debate with Kennedy even mean? As I learned when I argued with him about the 2004 election, trying to fight misinformation with facts is a tricky business. One side is bound by clearly documented evidence; the other side is free to cherry pick factoids from anywhere, to assert that establishment institutions are inherently suspect and that efforts to fact-check their claims amount to nit-picking, and that anyone who doesn’t see a bigger narrative in a collection of loosely related stories is, in effect, a naïf.I was a reporter at Salon during the 2004 election cycle. I’d spent several months before Election Day covering the ways America had been changing its voting systems since the fiasco of 2000, including the adoption in some places of electronic voting machines that could be vulnerable to hackers or other security lapses. Throughout that time I’d cultivated many sources in the insular, nerdy world of election administration and I’d become familiar with the minutiae of how elections are run.This left me well-prepared for what happened after Election Day — a barrage of theories from people on the left that, due to the electronic voting machines or other problems, the election had been stolen. In his Rolling Stone piece, referring to George W. Bush, Kennedy wrote that he’d “become convinced that the president’s party mounted a massive, coordinated campaign to subvert the will of the people in 2004.” He argued that in Ohio, where Bush’s victory put him over the top in the Electoral College, enough Kerry votes were uncounted, flipped or otherwise kept out of the race to cast doubt on Bush’s roughly 118,000-vote margin in that state.I investigated many of these theories, often by consulting the sources I’d cultivated. Kennedy was right that the 2004 election had been rife with irregularities and efforts at disenfranchising voters, particularly in Ohio, where a partisan secretary of state, Kenneth Blackwell, had overseen several divisive voting measures and obstacles. But pretty much every expert I talked to said that none of the issues were likely big enough to have undone Bush’s win. An investigation by the Democratic National Committee which looked at precinct level voting counts found that the data “does not suggest the occurrence of widespread fraud that systematically misallocated votes from Kerry to Bush.”And so: I wrote a point-by-point debunking of Kennedy’s breathless claims. Then Kennedy wrote a rebuttal to my rebuttal, which I, again, rebutted.For a week or two this dust-up took over my life. Salon, a generally liberal-leaning publication, was deluged by letters from readers angry that I was defending Bush’s win. Thankfully, my editors supported me, and I remember coming away from the episode feeling bruised but journalistically vindicated: A man with a famous political name was wrong on the internet, and, armed with the facts, I had stepped in to correct the record.Looking back, though, I cringe. The other day I went back and listened to a debate I had with Kennedy on public radio’s “The Brian Lehrer Show.” Lehrer opened the program by asking Kennedy for his big-picture case. But whether Kennedy is talking about vaccines, elections or other out-there topics (he told Rogan he is “aware” that he could be assassinated by the American government) he tends to present his theories in a particular way. He starts with a few sprinkles of truth — Ohio’s vote was run by a partisan official, some vaccines have serious side effects — and then swirls them up with enough exaggerations, omissions and leaps of logic to create a veritable McFlurry of doubt.Such was his effort when we met on Lehrer: Kennedy offered an assortment of claims about the election that, in big and small ways, were unsubstantiated. So when Lehrer turned to me, I felt I had no choice but to start out by correcting Kennedy’s misstatements. I did so pretty handily, but because I had to point to sources and tease out the nuances Kennedy had elided, I couldn’t help but sound like the boring, persnickety nerd stuck in the weeds. After a few rounds of this back-and-forth, I can’t imagine that much of anything had been clarified for the audience. Instead, the impression was one of earnest complexity: One side says X, the other says Y, but whoever is right, it sure seems like this is a debate we should be having.At one point, Kennedy even made this plain: “You’ll be able to dispute the numbers till the end of time,” he told Lehrer of the faults I found in his case. “Mr. Manjoo,” he continued, “has made a cottage industry of reciting the Republican talking points” by bringing up “arcane disputes of each of these numbers.” “The numbers are correct,” Kennedy claimed, but the arguments over facts were “almost a side issue.” The real story, he said, is that Republicans tried to suppress Democratic votes and “they probably succeeded or may or may not have succeeded in shifting the vote to President Bush, but they certainly tried, and the press has not covered this issue.”In other words: Each side has their own numbers. We’ll never know what actually happened. This guy sounds like a Republican. My story could be right. And isn’t it suspicious that no one is talking about it?Office Hours With Farhad ManjooFarhad wants to chat with readers on the phone. If you’re interested in talking to a New York Times columnist about anything that’s on your mind, please fill out this form. Farhad will select a few readers to call.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram. More