Colorado Sen. Michael Bennet joins 2020 presidential race

May 2 (UPI) -- Colorado Sen. Michael Bennet on Thursday joined the race for the 2020 Democratic presidential nomination, promising to improve the middle class and fix the U.S. political system.

Some expected Bennet, the second Coloradoan to run behind former Gov. John Hickenlooper, to announce his candidacy last month, but instead revealed he'd been diagnosed with prostate cancer. Bennet said on April 19 he's had successful cancer surgery and doesn't need any more treatment.

"We cannot be the first generation to leave less to our kids, not more," Bennet wrote in a Twitter post Thursday. "That's why I'm running for president. Let's build opportunity for every American and restore integrity to our government."

He also made the announcement on CBS This Morning.

"This country faces two enormous challenges, one is a lack of economic mobility and opportunity for most Americans and the other is the need to restore integrity to our government," he said.

Bennet is the latest to join a crowded Democratic field that includes former Vice President Joe Biden, Sens. Bernie Sanders, Cory Booker, Kirsten Gillibrand, Kamala Harris, Amy Klobuchar and Elizabeth Warren.

"I think he's a great candidate and I'd love to hear more from him. I knew [cancer] wasn't going to stop him," Helen Varner, who hosted an event for Bennet in Iowa this year, told the Denver Post.

Then-Gov. Bill Ritter appointed Bennet to a Colorado Senate seat in 2009 to replace Ken Salazar, who became interior secretary under President Barack Obama. Bennet then edged Republican Ken Buck to keep the seat the following year. He was re-elected in 2016.

Bennet said Thursday President Donald Trump in the White House has weighed on his mind.

"[I had] the feeling that we had gone in a very different direction than the one I believe we should be headed in," Bennet told KUSA-TV. "It doesn't have anything to do with Democratic or Republican, it has to do with the progress this country has made over generations to make us more free, more inclusive."