WASHINGTON — In a remarkable and lengthy rebuke of his party’s nominee, Senator John McCain sharply criticized Donald J. Trump’s comments about the family of a fallen Muslim Army captain, saying, “While our party has bestowed upon him the nomination, it is not accompanied by unfettered license to defame those who are the best among us.”
Mr. McCain, a war hero whose service and capture in Vietnam was also once derided by Mr. Trump, had stayed largely silent over the weekend as Mr. Trump’s feud with the parents of Capt. Humayun Khan brewed, waiting until Monday morning to release a prepared statement.
“In recent days, Donald Trump disparaged a fallen soldier’s parents,” he wrote of the parents, Khizr and Ghazala Khan. “He has suggested that the likes of their son should not be allowed in the United States — to say nothing of entering its service. I cannot emphasize enough how deeply I disagree with Mr. Trump’s statement. I hope Americans understand that the remarks do not represent the views of our Republican Party, its officers or candidates.”
Reverence for the military has been at the core of Mr. McCain’s career — he was his party’s nominee in 2008 and serves as chairman of the Senate Armed Services Committee — and he has a close allegiance to families of those killed in conflict. Mr. McCain is now in a tough re-election battle in his home state of Arizona.
While his statement, like that of congressional Republican leaders, fell short of rescinding his reluctant endorsement of Mr. Trump, it was a detailed and personal condemnation.
“I wear a bracelet bearing the name of a fallen hero, Matthew Stanley, which his mother, Lynn, gave me in 2007 at a town-hall meeting in Wolfeboro, New Hampshire,” Mr. McCain wrote. “His memory and the memory of our great leaders deserve better from me.”
“Make no mistake: I do not valorize our military out of some unfamiliar instinct,” he wrote. “I grew up in a military family, and have my own record of service, and have stayed closely engaged with our armed forces throughout my public career. In the American system, the military has value only inasmuch as it protects and defends the liberties of the people.”
He added: “In the end, I am morally bound to speak only to the things that command my allegiance, and to which I have dedicated my life’s work: the Republican Party, and more important, the United States of America. I will not refrain from doing my utmost by those lights simply because it may benefit others with whom I disagree. I claim no moral superiority over Donald Trump. I have a long and well-known public and private record for which I will have to answer at the Final Judgment, and I repose my hope in the promise of mercy and the moderation of age. I challenge the nominee to set the example for what our country can and should represent.”
Mr. McCain’s family has also been critical of Mr. Trump. His daughter Meghan McCain said on Twitter on Saturday: “I would ask what kind of barbarian would attack the parents of a fallen soldier, but oh yeah it’s the same person who attacks POW’s.”
In a post on Medium under the headline, “For this Republican, Never Trump means ‘I’m With Her,’ ” his granddaughter Caroline went further, saying Mr. Trump “lacks the temperament and the wisdom to navigate our ever-increasingly dangerous world.”
“Policy decisions aside, being president of the United States requires a steady hand — and never more so than now,” she wrote. “A competent commander-in-chief must respond to threats to the republic, but Trump only responds to threats to his ego.”
Mr. McCain has also been a vocal proponent of American military aid in Ukraine and was almost certainly rankled by Mr. Trump’s comment over the weekend suggesting that President Vladimir V. Putin of Russia was not involved in military moves into the area in spite of the fact that he seized the Crimean Peninsula.
Despite the intensifying criticism from Republican Party leaders, Mr. Trump on Monday showed no sign of relenting in his clash with the Khan family. He has not apologized for his suggestion that Ms. Khan might have been forbidden from speaking at the Democratic convention, and he has not yet acknowledged the mounting criticism from respected Republicans like Mr. McCain.
Instead, the Trump campaign has tried to shift attention away from their candidate’s comments about the Khans and toward broader issues of national security, including Mr. Trump’s proposals to clamp down on immigration. In an emailed statement from Mr. Trump on Saturday evening, and a follow-up statement from Gov. Mike Pence of Indiana, his running mate, on Sunday, the campaign argued that the focus of the race should be on stopping terrorism.
But Mr. Trump on Monday morning continued to criticize Mr. Khan personally, complaining that the he had become a ubiquitous presence in the news media since his Thursday address at the convention in Philadelphia in which he denounced the Republican presidential nominee.
“Mr. Khan, who does not know me, viciously attacked me from the stage of the DNC and is now all over T.V. doing the same,” Mr. Trump wrote on Twitter. “Nice!”
In a second post Mr. Trump shifted course and said the campaign should be focused on terrorism instead of the personal feud he has continued to feed. “This story is not about Mr. Khan, who is all over the place doing interviews, but rather RADICAL ISLAMIC TERRORISM and the U.S.,” he wrote. “Get smart!”
Democrats have already used Mr. Trump’s treatment of the Khan family to reopen past controversies surrounding Mr. Trump, including his mockery last summer of Mr. McCain’s service in Vietnam and his time as a prisoner of war. At a campaign stop in Youngstown, Ohio, on Saturday, Bill Clinton likened Mr. Trump’s harshness toward the Khan family to his ridicule of Mr. McCain.
But Mr. Clinton suggested Mr. Trump’s handling of the Khans was even worse, because their son did not survive the Iraq war.
“I was crazed by the attack on Senator McCain. But at least he survived,” Mr. Clinton said. “That man gave his life for his unit.”