The Iowa caucuses, the first nominating contest of the 2020 election cycle, begin this week. There are 41 pledged delegates up for grabs in the Democratic race, plus an additional eight unpledged (superdelegates) from Iowa.

All eyes are on Vermont Senator Bernie Sanders who has taken a lead in recent polling in the state. If he is able to gain more delegates than former Vice President Joe Biden tonight then it is increasingly likely he could win his neighboring state New Hampshire next week which will worry establishment Democrats.

There are a total of 1,679 precincts that will meet to caucus. The Democratic Party in Iowa will also hold a number of "satellite" caucuses for those who are unable to travel to a caucus location.

At most Democratic caucus locations, a candidate must get support from at least 15 percent of attendees to achieve viability. If that threshold isn't met, a candidate's supporters must realign to a different viable candidate or join with other nonviable groups to form a viable preference group. The Democratic "winner" is the candidate who accrues the most state delegate equivalents after the realignment process.