Businessman Tom Steyer, told reporters at an Iowa City campaign stop that while he would support publicly funded elections, he is unsure if his largely self-funded campaign would be in the same position under that system.

Steyer is among the six candidates who have qualified for the Dec. 19 presidential debates. A day earlier, Sen. Cory Booker of New Jersey campaigned in Iowa City, criticizing what he called the Democratic National Convention’s artificial barriers to qualifying for the debate. Booker has not yet qualified to be on the December debate stage, and both Steyer and Booker are polling at 3 percent in Iowa, according to the latest Iowa poll.

Steyer, a billionaire, has spent more than $47 million of his own money on his campaign, according to Open Secrets. Steyer started a hedge fund business in 1986, never received financial help from his parents, and has pledged to give half of his money to charities.

“I’ve put my heart and soul and my money to correct wrongs,” Steyer told a group of about 40 on Sunday at Java House. “This (election) is going to be a question of message.”

In 1986 Steyer founded Farallon Capital Management, a hedge fund primarily known for its management of university endowments. Steyer later became more involved in the Democratic Party, becoming an environmental activist and creating NextGen in 2013, a national get-out-the-vote campaign.

Steyer told reporters that he thinks the DNC’s requirements to get on the debate stage are too restrictive, but added that campaign messaging will be the most important factor in determining this election.

“I think the point about publicly funded campaigns means that if you are running, the public will fund a campaign that’s at least comparable to what anyone’s going to spend on their campaign,” Steyer told reporters. “And that’s actually I think the easiest way to go about this and the proper way.”

A publicly funded election system would divert tax dollars to political campaigns with the intent of giving each candidate the same amount of financial resources.

An attendee at the event asked Steyer if he would consider a way to get his message across in a way other than a bombardment of advertising in Iowa. Steyer has spent more than any other candidate on online, television, and radio advertising. As of Oct. 20, Steyer has spent more than $13 million on television advertising and $3 million on Google and Facebook advertising, according to the Wesleyan Media Project.

“If we’re going to beat Republicans, then we need someone who is going to go at Mr. Trump’s supposed strength,” Steyer said in response to the attendee’s question. Steyer said the race will change once it reaches the general election, where it will be more focused on issues.

Another attendee told Steyer that she’s concerned his message will get lost in his money, and mentioned comments from former presidential candidate Kamala Harris, who said in her departure announcement that she couldn’t fund her own campaign because she’s not a billionaire.

Steyer said that he wants to run a campaign that people can trust. Steyer has made climate change a main focus of his campaign, often saying he will declare a state of emergency on day one as president.