A Democratic campaign that has cost more than $1 billion, dashed the ambitions of veteran politicians, forced conversations about race, gender and identity and prompted fierce debate over health care and taxes crests Monday in the Iowa caucuses.

By day’s end, tens of thousands of Democrats will have participated in the famed Iowa caucuses, the premiere of more than 50 contests that will unfold over the next five months. The caucuses will render the first verdict on who among dozens of candidates is best positioned to take on President Donald Trump, whom Democratic voters are desperate to beat this fall.