WASHINGTON — A day after committing the nation to a new mission against Islamist terrorism, President Barack Obama honored the victims of the Sept. 11, 2001, attacks, 13 years after four hijacked planes plunged the United States into a decade of war against distant enemies.

Speaking before a giant American flag draped over the part of the Pentagon wall where one of those planes crashed, Mr. Obama said, “Thirteen years after small and hateful minds conspired to break us, American stands tall, and America stands proud.”

He hailed the “9/11 generation” of soldiers who served in the years after the 2001 attacks, and noted that “three months from now, our combat mission in Afghanistan will come to an end.”

For Mr. Obama, the Sept. 11 anniversary lent historic and emotional resonance to his announcement Wednesday night of a new mission against the Islamic State in Iraq and Syria. But it also carries a somewhat dissonant message: The president has labored to distinguish the expanded fight against ISIS from the wars in Iraq and Afghanistan.

The president on Thursday made no mention of ISIS, speaking only of challenges facing the country. But his description of a nation coping with the threat of terrorism seemed entirely relevant to what is happening now. “We carry on because as Americans, we don’t give in to fear — ever,” he said.

In some ways, this anniversary was no different than its 12 predecessors. It was filled with familiar rituals – a moment of silence, the playing of taps by an Army bugler, the assembled families of the victims, many now with children who have grown into adulthood.

Earlier on Thursday, Mr. Obama and the first lady, Michelle Obama, along with Vice President Joseph R. Biden Jr. and his wife, Jill, took part in a solemn ceremony on the South Lawn of the White House at 8:46 a.m., when the first plane struck the World Trade Center.

Later in the day, as they do every year, Mr. and Mrs. Obama will take part in a volunteer project. The president will otherwise remain at the White House, having lunch with Mr. Biden and meeting in the afternoon with his new secretary of Health and Human Services, Sylvia Mathews Burwell.

But Mr. Obama is also certain to be immersed in the details of the military campaign against ISIS that he outlined Wednesday night in his speech to the nation. His warning about the challenges to come still hung in the air, even as he marked the anniversary of battles past.

Americans born after Sept. 11, 2001, are now teenagers, Mr. Obama noted, and he said this post-9/11 generation gave him hope that the United States would remain resilient in the face of terrorist threats.

“Generations from now, Americans will fill our parks, our stadiums, our cities,” he said. “Generations from now, Americans will still build towers that reach toward the heavens, still serve in embassies that stand for freedom around the world, still wear the uniform

“Generations from now, no matter the trial, no matter the challenge,” he said, “America will always be America.”

article by Mark Landler via nytimes.com