On Monday night, Melania Trump, the wife of soon-to-be Republican presidential nominee Donald Trump, stood in front of thousands of people gathered at the Republican National Convention, and millions more watching on television, and gave a speech that clearly borrowed heavily from one given by Michelle Obama in 2008. The video evidence is undeniable.

The accusations of plagiarism were swift and numerous. "Two full paragraphs from the current first lady is just incomprehensible," former Obama speechwriter Jon Favreau told BuzzFeed. "I can't believe someone would do that to her." The Trump campaign was quick to respond on the defensive. "In writing her beautiful speech," they said in a statement, "Melania's team of writers took notes on her life's inspirations, and in some instances included fragments that reflected her own thinking. Melania's immigrant experience and love for America shone through in her speech, which made it such a success." Trump campaign chair Paul Manafort went as far as to dismiss the plagiarism allegations as "just really absurd," and explained that there was overlap simply because "these are common words and values."

But the speech speaks for itself. In one passage, 22 out of Melania's 26 words were taken directly from Michelle Obama's address. This is plagiarism.

Another Republican presidential nominee might emerge from this unscathed. One with a unified party, a disciplined message operation, and a reputation for honesty and goodwill could easily survive a mistake of this kind. But Donald Trump is not that candidate, and this will hurt his campaign.

Trump has utterly failed to unify the GOP. He has not made gestures to bring together warring wings of his party, nor to smooth over hurt feelings. This continued well into the convention itself. Indeed, 44 percent of Republicans say they would have preferred to nominate someone else. Instead of giving voice on Monday to delegates chosen to represent other candidates, Trump's convention parliamentarian shut down a vote asking for a roll call of credentials. Trump would have won this roll call, surely a show of strength. But the orders from on high would not allow an inch of ground to be ceded. The visuals from the convention floor were dreadful.

As for discipline, Trump has none. That's one reason he is admired; he makes gut calls and changes his mind on the fly. But this rarely works out for him. What about honesty? A lie a day from Trump is the norm.

But surely Melania, a political novice, deserves the benefit of the doubt. Surely we can forgive her one instance of plagiarism.

This probably isn't even Melania's fault. While she told NBC's Matt Lauer earlier on Monday that she wrote the speech virtually by herself, her campaign now says the speech was written for her by a team who interviewed her, cobbled something together, and then sent her a draft for her editing. But that team apparently failed to run the speech through any one of the pretty good online plagiarism checkers.

The big issue is the audacity of the ideas Melania Trump (or Trump campaign staffers) stole. Her husband has been at the vanguard of the movement designed to question Barack Obama's patriotism, his religion, and his identity. Donald Trump has insinuated, at least twice in the last month, that Obama has ulterior motives when dealing with ISIS and terrorism. He accuses Obama of deliberately sowing the seeds of racial dissent. He has warned of racial unrest.

Monday night, on a national stage, a white woman appropriated heartfelt words from a black woman whose husband has been the target of a ruthless and concentrated dehumanization campaign from the husband of the white woman.

This sin is not forgivable.