In a statement issued by the campaign, Meredith McIver took the blame but made it clear that Mrs. Trump knew the passages were from the first lady's speech.
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"A person she has always liked is Michelle Obama," McIver says of Mrs. Trump. "Over the phone, she read me some passages from Mrs. Obama's speech as examples. I wrote them down and later included some of the phrasing in the draft that ultimately became the final speech."
The passages in question came near the beginning of Mrs. Trump's nearly 15-minute speech.
In one example, Mrs. Trump said: "From a young age, my parents impressed on me the values that you work hard for what you want in life, that your word is your bond and you do what you say and keep your promise, that you treat people with respect."
Eight years ago, Mrs. Obama said: "And Barack and I were raised with so many of the same values: like, you work hard for what you want in life, that your word is your bond, that you do what you say you're going to do, that you treat people with dignity and respect."
There were similar overlaps in a passage dealing with conveying to children that there is no limit to what they can achieve. Mrs. Trump's address was otherwise distinct from the speech that Mrs. Obama gave when her husband was being nominated for president.
McIver, co-author of some of Donald Trump's books, said she offered to resign but the Republican nominee for president refused to accept her resignation.
"I did not check Mrs. Obama's speeches. This was my mistake, and I feel terrible for the chaos I have caused Melania and the Trumps, as well as to Mrs. Obama. No harm was meant."
McIver was described in the statement as an "in-house staff writer at the Trump Organization."
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