Others have defended the president, saying that the White House did not disrespect McCain's passing since the US Flag Code, American flags are only meant to be lowered "on the day of death and the following day for a Member of Congress", which is the procedure the White House followed.
The absence of a formal White House statement has underscored Trump's isolation in a city where McCain's death otherwise has been a rare occasion for bipartisan praise for his lifetime in public service.
Flags are typically flown at half-staff on a president's executive order until the day of internment, which is scheduled for Sunday at the Naval Academy.
While the flags at the White House were raised, the flags at the U.S. Capitol remained at half-staff on Monday to honor the Arizona Republican.
Travis Gettys is an editor for Raw Story.
Trump was not invited to McCain's funeral, which will include speeches from former presidents Barack Obama and George W. Bush.
- CJ (@CJintheKeys) August 27, 2018This morning I woke up to find out the White House flag is at full staff. But presidents have the power to issue proclamations extending that period.
McCain and Trump had a contentious history. John McCain's (R-Ariz.) death on Saturday.
ABC News correspondent Karen Travers - among other journalists - tweeted a photo of the White House as of Monday morning, however, which showed the White House flags back at full staff.
Throughout Trump's presidency, McCain did not hesitate to speak candidly about policy differences with Trump, including the president's friendly posture toward Russian President Vladimir Putin.
Trump, who regularly denounces that vote at his rallies, earlier this month repaid his nemesis by signing the John McCain National Defense Authorization Act without ever speaking the name of the person it was meant to honor.
McCain's rebuttals were generally measured, in contrast to the president's brash rhetorical style.