President Donald Trump and former FBI Director James Comey have given very different public accounts of the handful of times the two spoke before Trump abruptly fired Comey in May. 

Comey laid out his version of events before the Senate Intelligence Committee on Thursday, detailing comments the president had made to him about the FBI’s investigation into links between Russia and the Trump campaign and its probe of Trump’s former national security adviser, Michael Flynn. Comey’s account suggests that the president attempted to interfere with the bureau’s investigations, pressed the then-FBI director to pledge Trump his loyalty and asked him to “get out” the word that the president wasn’t personally under investigation. 

Trump, his personal lawyer and his staff have denied this account. 

When it comes to finding out what exactly transpired during those private meetings and phone calls (assuming there are no secret recordings), it’s Comey’s word against Trump’s. Who, then, is more credible?

One of these two men is lying.

I wonder if it’s the guy who served 3 presidents from 2 parties or the one who said Obama is from Kenya? pic.twitter.com/UBlJFw4zae

— Mikel Jollett (@Mikel_Jollett) June 8, 2017

There are several key points on which Trump and Comey differ: 

• Comey said that during a Jan. 27 meal, Trump told him, “I need loyalty, I expect loyalty.” Trump’s private attorney, Marc Kasowitz, said the president “never” asked for loyalty “in form or substance.” 
• In a May interview with NBC News’ Lester Holt, Trump claimed the January meeting took place because Comey “wanted to have dinner” with the president. On Thursday, Comey said it was actually Trump who invited him to dine at the White House. 
• Comey, Attorney General Jeff Sessions and other officials attended a briefing at the White House on Feb. 14. According to Comey, Trump asked to speak to him alone after the briefing and, during the ensuing conversation, said he hoped “you can let this go,” in reference to the FBI’s investigation of Flynn. Trump has denied this.
• After Trump fired Comey on May 9, Trump administration officials claimed the FBI rank and file had lost faith in their director. Comey testified Thursday that “those were lies, plain and simple.” 
• Trump has repeatedly denied that Russia interfered in any way in the 2016 election, dismissing the story as “fake news.” During Thursday’s hearing, Comey said he has “no doubt” that interference did happen. “That’s about as unfake as you can possibly get,” he said.

As Sen. Martin Heinrich (D-N.M.) put it during Thursday’s hearing, “a lot of this comes down to who we should believe.”

Comey, who was confirmed as FBI director in 2013, has spent much of his career at the Justice Department. While he was registered as a Republican for most of his adult life, he has served presidents in both parties (including Bill Clinton and George W. Bush) and is known as nonpartisan. 

By most accounts, Comey was well respected within the FBI and has a reputation as a person of integrity — a reputation that was solidified back in 2007, when he offered damning testimony about warrantless domestic spying during oversight investigations of the Justice Department under then-Attorney General Alberto Gonzales. Senators in both parties praised Comey while questioning him on Thursday, with many remarking on his candor and honesty. 

Perhaps the largest stain on his record involves his handling of the investigation into Hillary Clinton’s use of a private email server as secretary of state. Comey drew intense criticism from Republicans when he said that no charges would be pursued against Clinton, then running for president. But the greatest outcry came when Comey publicly announced that the FBI might re-open the investigation just days before the presidential election. Many Democrats, including Clinton herself, have partially blamed Trump’s victory on that announcement. 

Comey himself has said that decision caused him personal anguish, but that it arose from a desire to preserve the reputation and credibility of the Justice Department.  

“Look, this was terrible. It makes me mildly nauseous to think that we might have had some impact on the election, but honestly, it wouldn’t change the decision,” he said at a congressional hearing in May.  

Trump’s credibility, meanwhile, is debatable at best. The president and his team have repeatedly lied to the public, by HuffPost’s count perpetuating 100 notable falsehoods within just the first 36 days of his administration. And polls show that a strong majority of Americans do not have much faith in Trump’s remarks on the Russia probe. (A much smaller majority do not trust Comey’s statements on the matter.) 

The president’s lies have ranged from the inconsequential, such as his insistence that his inauguration crowds were much larger than they actually were, to the potentially dangerous, like his unsubstantiated comments that millions of non-citizens voted illegally in the 2016 election. 

Trump has claimed that he saw footage of “thousands” of Muslims in the U.S. celebrating after the 9/11 attacks. (That’s been debunked.) He’s suggested that President Barack Obama ordered wiretapping on Trump Tower. (There’s no evidence this happened.) And he repeatedly perpetuated the myth that Obama is not a natural-born U.S. citizen. (Obama was born in Hawaii.) 

It’s now up to Robert Mueller, the former FBI director who was appointed as special prosecutor to oversee the Russia investigation after Comey’s firing, to determine which version of events he believes. Mueller, too, served under presidents from both parties and is known for his independence.