Republican presidential nominee Donald Trump on Wednesday stood behind his false claim that he was "totally against" the Iraq War from the beginning, making the assertion while speaking about his judgment.

“I was totally against the war in Iraq. You can look at Esquire magazine from '04, before that,” Trump told Matt Lauer during NBC’s “Commander-in-Chief Forum” Wednesday night, responding to a criticism Democratic nominee Hillary Clinton made earlier in the evening that Trump was not being honest about his position.

"I have taken responsibility for my decision. He refuses to take responsibility for his support," Clinton said during the first segment.

Trump regularly makes the claim that he opposed the Iraq War in an effort to draw a contrast with Clinton on foreign policy. The claim has been repeatedly debunked by independent fact checkers, though Lauer did not press him on the issue.

Trump was asked in 2002 during a radio interview with Howard Stern if he supported invading Iraq. He responded affirmatively: “Yeah, I guess so. You know, I wish the first time it was done correctly.”

In an interview with Fox News one day after the March 2003 Iraq invasion, Trump praised the effort while talking about the war’s impact on Wall Street.

“Well, I think Wall Street’s waiting to see what happens, but even before the fact they’re obviously taking it a little bit for granted, and it looks like a tremendous success from a military standpoint, and I think this is really nothing compared to what you’re gonna see after the war is over,” Trump told Fox News’s Neil Cavuto.

Trump did criticize the way the war was handled during a 2004 interview in Esquire, as he said, but that was more than one year after the invasion.

Trump also said — as he has before — that the Islamic State grew because the United States failed to “take the oil” in Iraq after invading that country, allowing the militants to use it to finance their operations.

Although the Islamic State has occupied parts of Syria where they have been able to pump and sell some oil, they have never occupied oil-producing areas of Iraq, where reserves are exponentially bigger. Iraq’s oil is in the Shiite south and in the north around Kirkuk and Kurdish areas.

The lack of oil in the Sunni-dominated parts of Iraq — the same areas occupied by the Islamic State — and the Iraqi government’s failure to share the country’s oil wealth with its Sunni population, is one of the reasons the non-oil deserts of western Iraq were fertile ground for militant growth.

Karen DeYoung contributed to this report.