Billionaire activist Tom Steyer ends his campaign for the Democratic presidential nomination

Rebecca Morin | USA TODAY

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WASHINGTON – Billionaire and activist Tom Steyer has ended his presidential campaign.

In his speech Saturday night, Steyer, 62, thanked his supporters and campaign staff, saying he "has zero regrets."

“There’s no question today that this campaign, we were disappointed with where we came out,” Steyer told the crowd in South Carolina. "Honestly, I can't see a path where I can win the presidency."

Steyer used his vast personal wealth to fund much of his campaign, had made climate change and campaign finance reform the focus of his candidacy. But that wealth also made him a target, of other candidates and some voters, who likened his run to trying to buy the presidency. (Forbes estimates Steyer is worth $1.6 billion.)

Despite his low polling nationally, Steyer put much of his resources into advertising in the four early voting states of Iowa, New Hampshire, Nevada and South Carolina. Ad-tracking firm Advertising Analytics says Steyer spent more than $186 million on ads during the race.

This deluge of advertising helped him get onto the debate stage even as some of his opponents with more defined political careers, such as Sen. Cory Booker and former Housing and Urban Development Secretary Julian Castro, struggled to make it onto the stage.

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His campaign bet on a stronger finish in South Carolina, and his wife went so far as to move to the state temporarily, but Steyer finished behind former Vice President Joe Biden and Sen. Bernie Sanders.

Despite the tens of millions of dollars he pumped into the Palmetto State, it was unclear whether Steyer was projected to earn any delegates in South Carolina by the time he had dropped out.

But he declared that meeting the people of South Carolina and America was "the biggest highlight" of his life.

"When the Lord closes a door, he opens a window,” Steyer said passionately. “I will find that window and crawl through it with you, I promise you that.”

Steyer announced his candidacy in July in a video posted on YouTube, where he also noted that he had signed the Giving Pledge, a "promise to give away half of your wealth while you're alive to good causes."

His candidacy came several months after he said he wasn’t going to jump into the race. Steyer said in January he was going to be "strengthening my commitment” to Need to Impeach, a group that organizes grassroots efforts to impeach President Donald Trump.

In addition to that organization, Steyer founded NextGen America, a climate-oriented advocacy group.

Steyer said Saturday that "of course" he will keep working to defeat Trump, despite the end of his candidacy.

"Every Democrat is a million times better than Trump," Steyer declared. "Trump is a disaster."

Contributing: Nicholas Wu, Savannah Behrmann