Colorado Sen. Michael Bennet announced Thursday morning he is running for president in 2020.

Bennet, a Democrat, announced on "CBS This Morning" he'll seek the nomination, hinging his announcement on the issues of economic mobility and restoring integrity in government.

"This country faces two enormous challenges, among others. 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. "If we keep going down this road, we're going to be the first generation of Americans to leave less opportunity, not more, to the next generation."

Bennet, 54, has served in the Senate since 2009 and formerly served as superintendent of Denver Public Schools from 2005 to 2009.

Sen. Michael Bennet, D-Colo., listens during a question and answer session with a small group of journalists at a hotel, as he visits Mexico City in 2017. Bennet jumped into the packed Democratic presidential primary on Thursday, announcing a 2020 campaign that had been stalled while he was treated for prostate cancer.

He had openly considered a run for president before his announcement. On April 3, he announced he had been diagnosed with prostate cancer. He said he detected the cancer early, and his "prognosis is good." Weeks later, his office told The Hill he was cancer-free after having surgery.

He enters a large field of Democratic candidates looking to unseat President Donald Trump.

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This article originally appeared on USA TODAY: Colorado Sen. Michael Bennet enters 2020 race for president