First Lady Jill Biden was not particularly delighted to see now-Vice President Kamala Harris selected to be President Joe Biden’s running mate, excerpts from a new book about the 2020 presidential race revealed on Tuesday.

“There are millions of people in the United States. Why do we have to choose the one who attacked Joe?” Jill asked an adviser to her husband's campaign, according to “This Will Not Pass: Trump, Biden, and the Battle for America’s Future” by the New York Times reporters Jonathan Martin and Alex Burns.

The First Lady said this in reference to a viral campaign moment during the Democratic presidential primary in June 2019. During the debate, Harris, an Afro-Asian American woman and former U.S. Senator from California, castigated Biden for his past opposition to integrated public school busing.

In her short-lived run for the presidency, this moment was the highest point for Harris. As Biden was still seeking a running mate, Harris reportedly called the exchange “just politics” while Biden allies told Politico that it was unlikely he would hold the move against her. This turned out to be true when Biden selected Harris to be his vice president in the end.

But Harris’ time at the White House has not been without difficulties. For weeks last year, the political press was brimming with rumors about Harris’ frustration with the portfolio assigned to her with some allies suggesting that she was being set up to fail.

Adjunct to this discontent was a stream of reports about high staff turnover in Harris’ office and stories that she was being pitted against other possible Democratic rivals for the White House in 2024 if Biden chooses not to run. The president has made clear that he would likely run again for re-election for a second term.

The book captures this period with excerpts that show Biden aides annoyance at the whirlwind of controversies that seemed to come out of her office. One aide, White House Communications Director Kate Bedingfield, reportedly said Harris herself was to blame for these problems, but she denied ever disparaging Harris.

At one point, Biden himself stepped in to tamp down on what was growing into a wider scandal within the White House. Bringing his aides together for a meeting, Biden issued a strong warning against any sniping against Harris or others within the White House.

According to the authors, he warned that if “he found that any of them was stirring up negative stories about the vice president, Biden said, they would quickly be former staff.”