Delay is announced shortly after frontrunner Joe Biden called for the convention to be rescheduled
Three ratings were changed in each case.
There are now six vacancies; Democrats control the body with 232 seats
The Ocean State is the 20th in our series leading up to the 2020 presidential election.
The previously scheduled date - April 28 - was to have been the 2nd busiest day on the 2020 Democratic calendar