President Ford was interviewed by the Washington Post’s Bob Woodward, but embargoed the interview until after his death. The portion of the interview that is getting the most play is where President Ford differed with the Bush Administration on the Iraq War. Specifically, portions of the interview are being excerpted and rehashed as news articles reporting that Ford had “had deep doubts about Iraq,” and he “doubted justifications for the Iraq war.” It is the various permutations of the latter characterization that reveals a disconnect between what the former president said and what the headline writers want to believe he said.
What the president really said about the Bush Administration’s justifications for the Iraq War was:

“Rumsfeld and Cheney and the president made a big mistake in justifying going into the war in Iraq. They put the emphasis on weapons of mass destruction,” Ford said. “And now, I’ve never publicly said I thought they made a mistake, but I felt very strongly it was an error in how they should justify what they were going to do.“

What Ford disagreed with was in Bush trying to justify invading Iraq based on WMD. From this can be inferred that Ford believed there were other justifications. And he said as much in an interview with Thomas DeFrank of the NY Daily News in May (also embargoed):

Ford was a few weeks shy of his 93rd birthday as we chatted for about 45 minutes. He’d been visited by President Bush three weeks earlier and said he’d told Bush he supported the war in Iraq but that the 43rd President had erred by staking the invasion on weapons of mass destruction.
“Saddam Hussein was an evil person and there was justification to get rid of him,” he observed, “but we shouldn’t have put the basis on weapons of mass destruction. That was a bad mistake. Where does [Bush] get his advice?”

So while President “Ford said he wouldn’t have invaded Iraq…” in 2004, he had come to support it in 2006. And to characterize his belief as being that the “Reasons for Iraq War ‘A Big Mistake’” is patently false. President Ford disagreed with the method of justification. That is different than saying the war itself wasn’t justified. The press has taken a report that Ford opposed the initial invasion, conflated it with his disagreement in how the war was justified and come up with a story implying that he disgreed totally with the entire war, from stem to stern, Instead, President Ford was much more nuanced in his analysis. I thought the mainstream press liked nuance?