DES MOINES — California billionaire Tom Steyer says he’s ready to do what’s politically inconvenient as president and seek constitutional changes that limit the time politicians can spend in congress to 12 years. He’d also ban corporate spending in politics.

“My message is super important and I am out there trying to make sure that people hear it as much as possible and understand why I can be trusted to take action and not just talk,” Steyer said during a recent Radio Iowa interview.

Steyer was in the state this weekend for a CNN town hall forum at Grinnell College. He addressed the recent resignation of an Iowa aide accused of offering contributions to legislators in exchange for a Steyer endorsement. Steyer said that was inappropriate and his campaign sought that person’s an immediate resignation. Steyer also sent a message to another billionaire who may enter the race in early 2020. Steyer said Michael Bloomberg needs to support a “wealth tax.”

“Not only is the income so unjust, so undemocratic and so unfair — the distribution of incomes — the distribution of wealth across society is an absolute scandal,” Steyer said on CNN.

Steyer is a former hedge fund manager who has spent at least $46 million on advertising for his presidential campaign. Before that, Steyer bankrolled the “Need to Impeach” campaign. On November 1, at the big Iowa Democratic Party fundraiser, Steyer chose to make Trump his primary target.

“Everybody you hear today is more honest, more coherent and more patriotic than the criminal who resides at the White House,” he said, to cheers from the Liberty and Justice Celebration crowd. “Everybody!”

Steyer, who has pledged his number one priority as president would be action on climate change, has been one of the Democratic Party’s most prominent environmental activists in the past decade.

“I started a company by myself…and I built a pretty big company,” Steyer told Radio Iowa. “Then I took the ‘giving pledge’ to give away the bulk of my assets while I’m alive to good causes. I walked away from that company and I’ve spent the rest of my life building coalitions of Americans to take on unchecked power and to push for broader democracy.”

Steyer announced this past January in Des Moines that he would not run for president, but changed his mind and entered the race in July.

“If you think that I’m right on my basic thesis, government is broken, you have to ask who will actually change the culture and get back to government by and for the people and the question is: ‘Is it going to be someone from the outside or someone from the inside?’” Steyer told Radio Iowa.

Steyer has been involved in voter turn-out efforts in Iowa since 2014 through a group he founded called NextGen America. That group’s still working to register younger voters and is active on 41 Iowa college and university campuses.