WASHINGTON -- President Trump won't be joining his wife in attending the memorial service of former first lady Barbara Bush, matriarch of a political dynasty that Mr. Trump often clashed with during his 2016 campaign.

The White House said Thursday that Mr. Trump would not attend "to avoid disruptions due to added security, and out of respect for the Bush Family and friends attending the service." Mr. Trump is expected to be at his Florida estate this weekend during Saturday's funeral in Houston for the wife and mother of presidents.

Sitting presidents, however, have not typically traveled to the funerals of former first ladies. Former President Barack Obama did not attend the 2016 funeral of Nancy Reagan or the 2011 funeral of Betty Ford, for example. Mourners at those services included then-first lady Michelle Obama, former President George W. Bush, and former first ladies Hillary Clinton and Rosalynn Carter.

Get Breaking News Delivered to Your Inbox

Flags have flown at half-staff over the White House and at Mr. Trump's Mar-a-Lago estate in Florida since Bush's death at the age of 92, and Mr. Trump added his voice to the tributes that have poured in for the wife of President George H.W. Bush and mother of President George W. Bush. Mr. Trump offered his condolences to the Bush family on Wednesday, calling Barbara Bush "a titan in American life. Her presence and character were engraved into America's identity."

The magnanimous comments stood in contrast to the fractious words that flew between Mr. Trump and the Bush family when the businessman-turned-presidential candidate effectively conducted a hostile takeover of a Republican Party once ruled by the Bush family.

During his anti-establishment presidential campaign, Mr. Trump often held out the Bush family as an example of the political status quo, and wielded anti-dynastic sentiment against both Jeb Bush, one of Mr. Trump's vanquished Republican rivals, and Hillary Clinton, his Democratic opponent.

Barbara Bush, for her part, said in a February 2016 interview with CBS News that Mr. Trump was like a "showman" and she didn't "know how women can vote for someone" like him.

Intermediaries describe little semblance of a relationship between Mr. Trump and members of the Bush family and a presidential appearance at the funeral would have brought more attention to the 2016 primary fight and potentially distracted from Barbara Bush's life and legacy.

Running as a political outsider, Mr. Trump often dismissed President George W. Bush's handling of the Iraq War and mocked Bush's younger brother, the former Florida governor, as "low-energy Jeb." Mr. Trump even sounded off on the nonagenarian Bush on Twitter in August 2015: "The last thing we need is another Bush in the White House. Would be the same old thing (remember "read my lips, no more taxes"). GREATNESS!" (Bush actually said, "Read my lips: No new taxes," during his 1988 convention speech -- a pledge that later hurt him politically).

Last fall, George W. Bush delivered a pointed speech that confronted many of the themes of Mr. Trump's presidency -- all without mentioning Mr. Trump by name. He cautioned that "bigotry seems emboldened," and the nation's politics "seems more vulnerable to conspiracy theories and outright fabrication."

Around the same time, Mark K. Updegrove's book, "The Last Republicans," was published, in which the elder Bush called Trump a "blowhard" and George W. Bush wondered if he would be the last Republican president. The elder Bush said he voted for Clinton in 2016 while George W. Bush said he voted for "none of the above."

A White House official said Joe Hagin, Mr. Trump's deputy chief of staff for operations, had served as the primary conduit to the Bush family in advance of the former first lady's funeral. Hagin is also a veteran of both Bush presidencies. The official spoke on condition of anonymity to describe internal discussions.

Doug Wead, a former special assistant to George H.W. Bush, said he expected an eventual degree of healing in the Bush-Trump relationship. He recalled the elder Bush once intervening in a fight between two staffers, telling them, "'If I can meet with Gorbachev, why can't they talk to each other?' I think that's in the Bush DNA."

Wead said the evolution of the Bush family's relationship with former President Bill Clinton could be instructive. Members of the Bush clan became close to Clinton after their presidencies, eventually setting aside the tough words of the 1992 presidential campaign. Clinton has made annual summer trips to the Bush family compound in Kennebunkport, Maine, to visit George H.W. Bush.

Bill and Hillary Clinton and Barack and Michelle Obama all plan to attend Barbara Bush's funeral, along with the current first lady.

Anita McBride, chief of staff to Laura Bush during her time in the White House, said Melania Trump's presence at Saturday's funeral would demonstrate that she "understands and respects the fact that this is a small club of women and it is part of our culture. Even if they don't see each other, they are at each other's funerals and often at each other's library openings."

McBride said while the Bush family may not have liked the rhetoric of the campaign, "they respect and stand up and salute the office of the president of the United States."