(DES MOINES, Iowa) — Sen. Michael Bennet, D-Colorado, hit the campaign trail in Iowa on Sunday with three events — his first since announcing his 2020 presidential bid.Bennet declared his candidacy on May 2, becoming the 21st candidate to join a crowded field of Democrats hoping to take on President Donald Trump in 2020. Bennet has long been considered a rising star within the party, and was considered a likely presidential contender.He held out on announcing his run following a prostate cancer diagnosis, stating he would only run if he was cancer-free. Doctors said the 54-year-old underwent “a completely successful” surgery in late April, “requiring no further treatment,” according to a statement released by a spokesperson for the campaign.Nearly in tandem with making his diagnosis public, Bennet and Sen. Tim Kaine, D-Virginia, reintroduced their Medicare-X legislation, which would create a new public option for health insurance. The public option was something that was originally part of the Affordable Care Act, but was rejected as an idea for being too far to the left.With progressive issues now pushed to the forefront in the current Congress, Medicare-X, which would not eliminate all private insurance, appears to be more moderate compared to Sen. Bernie Sanders’ Medicare-for-all plan.Bennet served as the chief of staff of fellow Democratic presidential candidate John Hickenlooper when he was the mayor of Denver in 2003. Bennet also served as the superintendent of Denver Public Schools in 2005,He was appointed senator of Colorado by then-governor Bill Ritter following the resignation of Ken Salazar, who left to become Obama’s interior secretary in 2009. Bennet was re-elected to the Senate in 2010 and 2016.Copyright © 2019, ABC Radio. All rights reserved.