President Obama prepares to speak at Arlington National Cemetery on Friday. (Pablo Martinez Monsivais/AP)

President Obama laid a wreath in Arlington National Cemetery on Friday and used his final Veterans Day speech to deliver a plea for unity and to urge Americans to set aside political grievances and follow the example of those who fight the country's wars.

"We can practice kindness, we can pay it forward, we can volunteer, and we can serve," Obama said on a blustery and bright day. "We can respect one another. We can always get each other's backs. That is what Veterans Day asks all of us to think about."

The president is a former smoker and during moments of stress he has admitted to chewing Nicorette gum. Before he stood to speak, Obama appeared to spit a wad of the gum into a paper napkin, which he slipped into his suit pocket. As he stepped to the presidential lectern, he was welcomed with an unusually long ovation.

The president, normally a polished and confident speaker, seemed to stumble over his words at the beginning of his address. He praised veterans for their quiet and selfless service, but the focus of his remarks was on the need for the country to recover from a bruising election campaign, a theme that is likely to dominate his remaining days in office. He praised the U.S. military as "the single most diverse institution in our country," representing "every shade of humanity … all forged into common service."

The president referred in the most general way to the bitter election campaign to replace him, which was marred by widespread accusations of racism, sexism and anti-immigrant sentiment. "Veterans Day often follows a hard-fought political campaign," he said.

But the president did not revisit the slights of the campaign trail, focusing instead on the  "the American instinct ... to find strength in our common creed, to forge unity from our great diversity."

"We can show how much we love our country by loving our neighbors as ourselves," Obama said.

The president defended his administration's record on veterans' issues, noting that he had increased funding for the Department of Veterans Affairs by 85 percent over the course of his two terms in office, improved access to mental health services and cut veteran homelessness in half. He urged his successor to continue work on the tragedy of veteran suicides, which claim 20 lives a day, and to resist calls to outsource and privatize the VA.

Obama focused his remarks on an increasingly disaffected and angry electorate. "Whenever the world makes you cynical, whenever you seek true humility and selflessness, look to a veteran," the president said.