Republican presidential candidate Donald Trump has been repeating some false statements over and over again. Here are the last four of his claims that the Post's Fact Checker gave Four Pinocchios. (Jenny Starrs,Michelle Lee/The Washington Post)

At the Fact Checker, we have often said we do not write fact checks to change the behavior of politicians. Fact checks are intended to inform voters and explain complicated issues.

Still, most politicians will drop a talking point if it gets labeled with Four Pinocchios by The Fact Checker or “Pants on Fire” by PolitiFact. No one wants to be tagged as a liar or misinformed, and we have found most politicians are interested in getting the facts straight. So the claim might be uttered once or twice, but then it gets quietly dropped or altered.

But the news media now faces the challenge of Donald Trump, the presumptive Republican nominee for president. Trump makes Four-Pinocchio statements over and over again, even though fact checkers have demonstrated them to be false. He appears to care little about the facts; his staff does not even bother to respond to fact-checking inquiries.

But, astonishingly, television hosts rarely challenge Trump when he makes a claim that already has been found to be false. For instance, Trump says he was against the 2003 invasion of Iraq, but research by BuzzFeed found that he did express support for an attack. He said the White House even sent a delegation to tell him to tone down his statements —and we found that also to be false.

Yet at least a dozen television hosts in the past two months allowed Trump to make this claim and failed to challenge him. There is no excuse for this. TV hosts should have a list of Trump’s repeated misstatements so that if he repeats them, as he often does, he can be challenged on his claims.

(On Thursday, Bret Baier of Fox News finally pressed Trump on his support for the Iraq War. “I said very weakly, well, blah, blah, blah, yes, I guess,” Trump responded.)

The online version of the Fact Checker keeps a running list of Trump’s Four-Pinocchio statements. He now has 26, which accounts for nearly 70 percent of Trump’s statements that have been fact checked.

Since many of these fact checks, done with my colleague Michelle Ye Hee Lee, have appeared only online, here is a summary of recent Four-Pinocchio statements made by Trump.

ISIS has the oil [in Libya]. ISIS is making a fortune now in Libya.

Trump often falsely suggests he opposed the intervention in Libya when he was actually an advocate for toppling Libya’s then-dictator, Moammar Gaddafi. He also has repeatedly made the bizarre claim that the terror group known as the Islamic State has control of oil fields and is making a fortune there.

Claudia Gazzini, a Tripoli-based senior analyst at the International Crisis Group, said it is simply not true that the Islamic State has control of any Libyan oil.

“While it is true that ISIS has attacked oil fields in the Sirte basin area and destroyed key equipment there, they have not sought to keep control of the oil fields,” Gazzini said. “At the moment, they appear to have adopted a hit-and-run strategy. There is no evidence that they are pumping out the crude oil and certainly no evidence that they are trading it.”

A review of recent news articles confirms that while some fields have been temporarily closed in response to Islamic State attacks, not a single field has been taken by the terrorist group.

There are scores of recent migrants inside our borders charged with terrorism

It took some time but we finally determined that this appears to be a bungled reference to a list from the office of Sen. Jeff Sessions (R-Ala.) of 30 foreign-born individuals who were arrested on charges relating to terrorism in recent years. This list is quoted in several articles and described as a “partial inventory of recently implicated terrorist migrants.”

We checked indictment records and looked for citizenship or immigration information, where available. The majority of the 30 cases involved naturalized U.S. citizens — people who came to the U.S. as children or had arrived before 2011.

We reviewed similar lists of cases from 2014 and 2015, involving 76 people charged with activities relating to foreign terrorist organizations. Of them, 57 were U.S. citizens, seven were lawful permanent residents, and two were refugees. The rest were visa overstays or unknown. There were both naturalized and natural-born U.S. citizens (including those of Caucasian, African American or Hispanic descent), and many of the naturalized citizens had arrived in the country as children.

In general, individuals must live in America at least five years with a green card to qualify for U.S. citizenship. The actual citizenship process can take up to a year or more. So even if Trump is counting naturalized citizens as “migrants,” the ones listed in these cases would not qualify as “recent.”

“You know who started the birther movement? Hillary Clinton. She’s the one that started it. She brought it up years before it was brought up by me.”

This zombie claim repeatedly has been debunked by fact checkers.

The allegation that Clinton herself was the first, or even one of the first, to question President Obama’s birth certificate is simply false. Trump might have been on safer ground if he blamed her supporters for stoking the birther rumors, which do have some Democratic roots.

In spring 2008, some of Clinton’s supporters began circulating anonymous emails questioning Obama’s citizenship. FactCheck.org and Politico cited these emails as the first time his citizenship was called into question, by a small group of “diehard” Clinton supporters during the Democratic primary as her path toward the nomination began to fade.

Chain emails surfaced claiming Obama was ineligible to become president because he was born in Kenya, as his mom was too young to travel by plane back to America to give birth. Others claimed Obama was refusing to release his full birth certificate because it likely contained information that he had dual Kenyan and U.S. citizenship at birth. But we found no evidence that Clinton or her campaign coordinated any of these email chains questioning Obama’s citizenship.

While some have pointed to a 2008 interview on “60 Minutes” in which Clinton said Obama was not a Muslim “as far as I know,” that quote has been taken out of context. She actually said that it was a “ridiculous” rumor and that there “isn’t any reason to doubt” Obama.

Russian President Vladimir Putin “called me a genius”

This is an exaggeration of a mistranslation.

After Putin’s annual news conference in December, he was cornered by a reporter for ABC News and asked what he thought of Trump.

Here’s how ABC News translated Putin’s remarks: “He’s a very colorful person. Talented, without any doubt, but it’s not our affair to determine his worthiness — that’s up to the United States voters.”

Russian is notoriously complex to translate into English, so various news organizations rendered the key quote in slightly different ways. Instead of “colorful,” The Washington Post said “lively.” The New York Times used “flamboyant.”

None of that sounds anything like “genius.” Some news organizations, such as the Guardian newspaper, used “bright.” The Guardian issued a correction a day later: “The word he used was ‘yarkii,’ which can mean bright or brilliant, but not in the sense of intelligent; it can also be translated as colorful, vivid or flamboyant.”

In other words, the Russian president said he regarded Trump as a “colorful” figure, which is not the same thing as someone with a 140 IQ.

No doubt about that. A colorful person may earn lots of Pinocchios; a genius does not.