38% of Iowa voters are not affiliated with a political party, they must be registered with a one in order to vote in a primary or caucus; but voters are allowed to change affiliation before the primary election or at the polls on primary day.
If a super-majority of Iowans oppose the grotesque amount of money in politics, like in most states, they can register their opposition by voting for one of the few 2020 Democratic Presidential candidates that if elected are more likely that the others to do something about it.
The DNC has opposed open primaries/caucuses every chance they get and by doing so can maintain the status-quo of big money politics which has caused more and more voters each year to abandon the two political parties.
2020 is an opportunity for, especially Independent Voters, to push-back on both closed primaries and big money politics.