Sen. Bernie Sanders Bernie SandersMcConnell accuses Democrats of sowing division by 'downplaying progress' on election security The Hill's Campaign Report: Arizona shifts towards Biden | Biden prepares for drive-in town hall | New Biden ad targets Latino voters Why Democrats must confront extreme left wing incitement to violence MORE (I-Vt.) evoked the legacies of Democratic presidents known for their advocacy for a robust social safety net and sweeping social change in his presidential campaign’s final Iowa ad ahead of Tuesday’s Democratic debate, the last one before the Iowa caucuses.

The 30-second spot, titled "Strive," opens with a clip of President John F. Kennedy’s famous speech in which he called for the U.S. to send a man to the moon, saying, “We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard.”

“President Kennedy knew settling for half-measures wasn't good enough,” Sanders says in voice-over over images from his own campaign as well as images from the Franklin Roosevelt and Lyndon Johnson administrations, the civil rights and women’s liberation movements, and protests for climate action.

“So when candidates say we can’t guarantee health care for all, make college affordable for all, combat climate change, or create a world at peace, remember that America is best when we strive to do big things, even when it’s hard,” Sanders adds.

Sanders’s more centrist competitors in the race, such as former Vice President Joe Biden Joe BidenCast of 'Parks and Rec' reunite for virtual town hall to address Wisconsin voters Biden says Trump should step down over coronavirus response Biden tells CNN town hall that he has benefited from white privilege MORE and South Bend, Ind., Mayor Pete Buttigieg Pete ButtigiegBogeymen of the far left deserve a place in any Biden administration Overnight Defense: Woodward book causes new firestorm | Book says Trump lashed out at generals, told Woodward about secret weapons system | US withdrawing thousands of troops from Iraq A socially and environmentally just way to fight climate change MORE, have frequently assailed some of his signature proposals, such as "Medicare for All" and forgiveness of student loan debt, as unrealistic.