November's presidential election posed a painful dilemma for retired General Colin Powell.

John McCain is "a beloved friend" for whom Powell has "nothing but the highest respect."

And yet, Powell told a Stanford audience Monday, there was something compelling about Barack Obama, who is about the age of Powell's own son, Michael.

Powell, a Republican and former U.S. secretary of state and chairman of the Joint Chiefs of Staff, has served under every U.S. president since Ronald Reagan. He said he was taken with Obama's vision, sense of purpose and "brilliant" use of modern communications technology.

Obama first approached him about running for president two years earlier, he said. But Powell, concerned about Obama's lack of experience, took a wait-and-see position.

When the economic crisis broke last fall, Obama "had some ideas but didn't pretend to have answers while the Republican Party came up with an answer: Joe the Plumber.

"That did it," said Powell, who then endorsed Obama.

"I felt Obama brought generational change and a transformational dimension to American and world politics that was needed," said Powell, who is 72.

Now on the lecture circuit and working with a variety of businesses and nonprofits, including a local venture capital firm and Google, Powell engaged a Stanford audience of more than 1,700 with jokes, stories and thoughts on the state of the world.

He was clearly enchanted with the products of Silicon Valley.

"I have to figure out how to Twitter with my grandchildren or I'm going to lose them," he said. He described Google as "scary and fascinating."

On election night, Powell was in a Hong Kong hotel preparing to address Chinese officials. "When Charlie Gibson said 'Barack Obama is the next president of the United States' -- even though I'd worked for it -- it still hit me like an electric shock.

"I had to sit down and start crying," said Powell, who is the son of Jamaican immigrants.

"We'd proven that we've reached a point in our national life where we could honestly say that the content of a person's character is more important than the color of a person's skin."

Despite the "sea change" he has seen in opportunities for minorities in America, America still has far to go, he said.

"The lingering problem of race is with us as long as we have minority kids going to substandard educational institutions and not having the same economic opportunities as other kids, with incarceration rates off the charts. We have to keep talking about it and keep finding opportunities."

A career soldier who rose to the rank of general by age 51, Powell told Stanford students a good leader is able to communicate passionately a vision and give subordinates the tools, skills and recognition to carry it out.

"Great leaders are those who can touch a human being and get a human being to work with you. It's that simple connection that draws out the best in people."

He described visiting the parking garage of the State Department while he was secretary of state, chatting with minority, low-wage workers about their jobs, the fumes, their working conditions. When he asked them how they prioritize parking spots, he was told, "If somebody stops, lowers the window, smiles and says, 'Good morning,' they're in front. If somebody keeps the window up and doesn't see a human on the other side of the glass, they're in back."

Economic development is the driving political issue in the "information-driven" world that no longer respects political boundaries and where money moves around at the speed of light, Powell said.

"If China and all these nations are industrializing, that places greater demand on the energy needs of the world. We need to do more exploration, conservation, find more alternatives and be less profligate. America has to be in the lead to find a solution to global warming."

Shortly after he stepped down from the State Department, Powell found himself singled out for an extra search in an airport security line. Despite the inconvenience, he recognized it as a "reasonable measure" he himself had put in place to protect against terrorism.

But Powell came to believe Americans were paying too high a price for their safety by throwing up barriers to foreign students and foreigners seeking to come for health care or simply wishing to visit.

"We were communicating a message that America is not a welcoming place to be and that was not good.

"Terrorists can get through if they work at it hard enough, but what they can never do is change who we are as a people -- only we can do that to ourselves.

"We must not be so concerned with these dangers that we lose the essence of who we are as a free, open and welcoming society because that's what makes our country great.

"America's position is evolving, but there's no doubt in my mind that we're still the place in the world that people look to. At every embassy and consular office there are people lined up saying, 'I want to go to America.'"

Powell told a story of stopping to buy a hot dog from a street peddler in Manhattan. When the immigrant vendor recognized his customer, he refused to let him pay. "I'm here; my family's here," the vendor said. "General, take the hot dog. I've already been paid."