CEDAR RAPIDS, Iowa -- Former New York Mayor Michael Bloomberg said in Iowa on Tuesday that he would do everything he can to make climate change the defining issue of the 2020 Democratic presidential nominating campaign, despite resistance in regions of the country that his party would likely need to recapture the White House.

More than 1,000 miles (1,600 kilometres) away in Charleston, South Carolina, fellow billionaire Tom Steyer -- who, like Bloomberg, is weighing a 2020 Democratic presidential bid-- held a roundtable discussion focused on voting rights in the nation's first Southern primary state.

The two deep-pocketed Democrats have been noncommittal about whether they will run for president in 2020, but on Tuesday they joined the growing list of visitors to early voting primary and caucus states. Bloomberg recently told The Associated Press that he would have to be close to a decision by mid-January. While travelling in Iowa on Tuesday, he said that, in the meantime, "I get to go around and to ask people in Iowa, 'What's on your mind?"'

In an interview, Bloomberg said he is still considering whether to run but didn't provide a timeline for when he'd decide.

"I am obviously thinking about what the right thing to do is, but I think honestly I know that there's a time by which I have to do something," he said. "I also think that there are going to be a lot of events over the next few weeks or very small number of months that are going to be important."

Steyer said he is closely watching the decisions made by other Democrats, joking, "I assume there are going to be more Democrats running than there are going to be voters."

While both men have put the climate atop their agendas, and spent millions promoting awareness and solutions, they could face skepticism in states such as Ohio, Pennsylvania and Michigan, where President Donald Trump won in 2016 by promising to protect the coal industry.

"I will do everything for sure to try to make it the issue," Bloomberg told reporters after visiting a solar-electric panel installation company in Cedar Rapids, Iowa. "Every place I have gone, people always want to talk about the climate. They always want to bring up the fact that I've been very active in closing coal-fired power plants."

Steyer on Tuesday turned his focus to voting rights -- one of the "five rights" in the platform he released last month, calling South Carolina the "perfect place" to begin that conversation.

"If you look historically, South Carolina has a long history of trying to make sure that people don't have equal votes," Steyer said at the start of the town hall. He called South Carolina a state that, "whether people here enjoy it or appreciate it or are sorry about it," plays an outsized part of the national conversation about the future of the country.

Both men have been sharply critical of Trump and agree that he is not fit for the presidency. Steyer, who has amassed a 6 million- person email list from his Need to Impeach campaign against Trump, has repeatedly said Trump is a danger to the country and must be ousted.

Speaking on Tuesday, Steyer described Trump as "the most corrupt president in American history who is a basic threat to our system and our safety and to the Constitution itself." He said that many politicians -- Democrats and Republicans -- "don't think it's good for their careers to talk about that."

Bloomberg, however, said, "It would be a mistake to say anything about that before you see what comes out of the investigation" being conducted by former FBI Director Robert Mueller into Russian election meddling.

Bloomberg and Steyer spent millions during the 2018 midterm campaigns on behalf of Democratic candidates. Their travel gave them new opportunities to test their message and, perhaps most importantly, gauge the interest of Democratic primary voters and activists in the potential candidacies.

In the Des Moines area, Bloomberg was visiting a community college's wind-energy program and was scheduled to meet with mothers organized to curb gun violence before attending a screening of his climate change film, "Paris to Pittsburgh."

Bloomberg contributed $250,000 to the Iowa Democratic Party this year, giving him some claim to gains such as capturing two Republican-held House seats last month. He also has plans to meet with key Democratic operatives. But other potential candidates, including Sen. Cory Booker of New Jersey, Sen. Elizabeth Warren of Massachusetts, Sen. Kamala Harris of California and Montana Gov. Steve Bullock, have been more aggressive in their efforts.

------

Summers reported from Charleston, South Carolina.