Billionaire Tom Steyer takes aim at 2020 Democratic competitors in economic speech

Steyer argues his business experience makes him best suited to beat Trump.

"[H]ere’s what American voters must understand: despite his racism, his lies, and his impeachable crimes -- if Democrats don’t nominate someone who can go head-to-head with him on the economy, Donald Trump will win in 2020," Steyer will say in Iowa on Monday, according to early excerpts released by his campaign.

"Look, I have a lot of respect for the four leading Democratic candidates in this race. But here’s the truth: none of them -- not Vice President Biden, not Senator Warren, not Senator Sanders, not Mayor Pete -- have built or run a successful, international business," Steyer will say in his remarks in Iowa City.

"None of them have a private sector track record of creating jobs -- none of them have first-hand experience growing wealth and prosperity," Steyer plans to say, according to his campaign.

Steyer is one of three billionaires running in the 2020 race, alongside former New York City Mayor Mike Bloomberg and President Trump, and has sunk over $40 million of his own money into his campaign through television ads and staff.

Steyer argues that Democrats saw in 2016 "the most experienced and qualified candidate in history," get defeated by Trump -- a signal that the party should think outside the box, and think about the issue that most often decides elections in 2020.

"If Democrats want to win in 2020, we need to realize that Donald Trump is a different kind of candidate, who presents different challenges than anyone who has come before him," Steyer is expected to say.

"Conventional wisdom won’t work against Trump. We need new thinking, and new leadership. And we know this will come down to the economy. Presidential elections always do."

But Steyer is still struggling to make headway in the Democratic primary, as several Democratic contenders have accused Bloomberg and Steyer, both of whom are self-funding their campaigns, of trying to buy their way onto the debate stage with such large spending, rather than focusing on grassroots fundraising.

Despite his poll numbers that remain in the single digits nationally, Steyer, who originally passed on a 2020 bid, has garnered enough support to appear in the last two primary debates, and has also qualified for Thursday's debate in Los Angeles.

ABC News' John Verhovek contributed to this report.