It’s a simple question, one that we ask candidates, campaigns and political committees all the time: “What evidence do you have?” We almost always get an answer. But that has not been the case with Donald Trump’s campaign, which typically does not respond to fact-checkers or provides scant information when it does.

That’s why we were heartened to see NBC’s Lester Holt ask Trump “what evidence do you have” to support two of Trump’s claims in a June 22 speech that we and other fact-checkers found contained numerous false claims.

Holt asked Trump about his claim that Clinton’s private email “server was easily hacked by foreign governments.” Trump went on to say “our enemies” probably even have the emails Clinton deleted, meaning they have a “blackmail file” on her. “This fact alone disqualifies her from the presidency,” Trump said.

But it is not a fact. As we wrote, there is no evidence that Clinton’s server was hacked — let alone by hostile foreign governments. We have written that the private server was not approved by the State Department, and it was the subject of security concerns within the department and a target of attacks outside the department. But there’s no evidence at this point that any of the attempts were successful.

Holt asked Trump, “What evidence do you have?” that her server was successfully hacked. When that didn’t elicit a response, Holt asked again, “But is there any evidence that it was hacked other than routine phishing?” Trump finally said that he heard or read about Clinton’s email being successfully hacked. Asked where he got that information, Trump said, “I will report back to you. I’ll give it to you.”

Holt asked Trump how he could make his claim “with such certainty” without evidence. Trump replied, “I don’t know if certainty. Probably she was hacked.”

Similarly, Holt pressed Trump on his claim that U.S. Ambassador to Libya Chris Stevens “was left helpless to die as Hillary Clinton soundly slept in her bed.” As we wrote, there is no evidence for that, either. We know that Clinton was involved in the government’s response to the attacks, which began at about 3:45 p.m. Eastern Daylight Time, and we know that she sent the last of two emails about Stevens’ death at 11:38 p.m. EDT.

We also know that she went home at some point during the attacks. She testified that she stayed up all night, but as we wrote, we cannot independently verify whether Clinton did sleep that night — but neither can Trump, and he admitted as much to Holt. Trump said “who knows if she was sleeping … she might have been sleeping.”

Holt isn’t the only one who has demanded evidence from a presidential candidate.

CNN’s Jake Tapper did the same earlier this month when he asked Trump to provide evidence to support the claim that Trump was opposed to the Iraq war before it started. There is no evidence of that, either, as we have written. Trump responded to Tapper by saying, “I think there is evidence. I will see if I can get it.”

And CBS’ Charlie Rose, reading from one of our articles, asked Democratic candidate Bernie Sanders in April about his claim that Clinton relies heavily on campaign contributions from the oil and gas industry. Sanders’ response to Rose was misleading, so we wrote about that, too.

But these are exceptions rather than the rule. As Washington Post Fact Checker Glenn Kessler has written, “astonishingly, television hosts rarely challenge Trump when he makes a claim that already has been found to be false,” adding that Trump’s campaign “does not even bother to respond to fact-checking inquiries.”

We, too, would like to see more TV news anchors challenge the presidential candidates on statements that fact-checkers universally agree are false and misleading, especially those that are made without any evidence. It just takes a simple question, “What evidence do you have?”