ERIC THAYER / Reuters Donald Trump attends a campaign event in Columbus, Ohio, last week. The GOP candidate's unsupported claims of "rigged" voting threatens American democracy itself, says CNN's Brian Stelter.

Donald Trump, currently down in the polls, has taken to attacking the system.

In speech after speech, interview after interview, the Republican presidential nominee has claimed ― without providing a shred of evidence ― that the election is “rigged” against him.

It’s an absurd, incredibly dangerous argument to make, CNN’s Brian Stelter pointed out Sunday, adding that journalists must do a better job of questioning Trump about his claims.

“Interviewers, even ones who support the person they’re interviewing, have an obligation to probe further and push back when a candidate says something dangerous,” Stelter said. “And this is dangerous.”

Trump's talk about a "rigged election" is dangerous, and journalists should treat it that way, @brianstelter says https://t.co/MHZS5y0rLU — Reliable Sources (@ReliableSources) August 8, 2016

Stelter specifically called out Bill O’Reilly and Sean Hannity for failing to press Trump on the matter when they had the chance.

“Journalists cannot just play these soundbites, quote these claims, and then move on to the next subject,” Stelter said. “We can’t just let it seep into the discourse like it’s normal. We have to stop and fact check and contextualize.”

That burden falls on all journalists, regardless of which candidate they personally support, he added. Unsupported claims that seek to undermine our entire political process must be countered.

Perhaps Trump could learn a thing or two from Al Gore, who gracefully conceded in 2000, amid an historically anomalous vote, ultimately decided by the Supreme Court, for the sake of American democracy.

“Let there be no doubt: While I strongly disagree with the court’s decision, I accept it,” Gore said at the time. “And tonight, for the sake of our unity as a people and the strength of our democracy, I offer my concession.”

Editor’s note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims ― 1.6 billion members of an entire religion ― from entering the U.S.