Originally Published: 18 OCT 21 12:32 ET

Updated: 18 OCT 21 12:46 ET

Analysis by Jeff Zeleny, Chief National Affairs Correspondent

(CNN) -- With two weeks remaining in the historic 2008 presidential race, Colin Powell delivered a surprise announcement: He endorsed Democratic candidate Barack Obama and offered words of regret to his old friend, John McCain.

"I think we need a generational change," said Powell, the former secretary of state, chairman of the Joint Chiefs of Staff and retired Army general.

At the time, it was a bombshell that neither Obama nor McCain -- a fellow Republican -- was expecting.

Powell barely knew Obama, the junior senator from Illinois, but he had been watching his presidential campaign carefully and was impressed by what he called Obama's "intellectual vigor." His assessment of the McCain campaign was far less charitable, from selecting Sarah Palin to serve as his running mate to what he viewed as a scattershot approach to the economic crisis.

"It isn't easy for me to disappoint Sen. McCain in the way that I have this morning," Powell said in an interview on NBC's "Meet the Press," where he delivered the news that helped shape the final days of the campaign.

In the long public life of Colin Luther Powell, who died Monday at the age of 84, that decision offers a brief, yet important window into his view of the American presidency. He saw the office from the highest corridors of power, serving in three Republican administrations, but he believed Obama represented the future.

"He is a new generation coming into the world, onto the world stage," said Powell.

Powell, who served as the nation's first Black secretary of state and the first and only Black chairman of the Joint Chiefs of Staff, bristled at the suggestion that he endorsed Obama because he would be the first Black president. Instead, he explained at the time and over the last decade, he supported Obama because he didn't like the darkening political discourse in America.

"We have come to live in a society based on insults, on lies and on things that just aren't true," Powell said in 2018. "It creates an environment where deranged people feel empowered."

Powell would go on to endorse Hillary Clinton in 2016 and Joe Biden in 2020 -- both longtime acquaintances and friends in Washington -- as he continued to speak out against the changing face of the Republican Party.

Today, his voice was hardly alone among party elders amid the rise of Donald Trump.

But 13 years ago this week, when Powell unveiled his support for Obama, the weight of his words shook the presidential campaign in a way that few other endorsements did. He did not hit the campaign trail for Obama in the final days of the race, but simply made his views clear.

"A great soldier, a great statesman and a great American has endorsed our campaign to change America," Obama said on that day, after learning the news.

Looking back, even McCain's reaction is astonishing in today's vitriolic politics.

He told advisers and friends at the time that he was deeply disappointed, but said only these words publicly: "I respect and continue to respect and admire Secretary Powell."