Decisions by conservative courts come barely 12 hours before the polls open
New Florida poll shows 46% of registered voters would vote for likely presidential candidate Joe Biden, with 40% voting for Donald Trump.
Meanwhile, Republicans said they feel confident they can still pull off their convention in Charlotte, North Carolina, that same month.
Pennsylvania is the latest state to postpone its presidential primary because of the outbreak. As of Friday, 19 counties were under a stay-at-home order.
The cost of postage alone for vote-by-mail is estimated at $423 million, and an additional $170 million if Congress opted for prepaid postage.
The controversial 38-year-old congresswoman from Hawaii made the announcement in a four-minute video.
Biden's third big night in as many weeks came Tuesday amid tremendous uncertainty as the Democratic contest collides with efforts to slow the spread of the novel coronavirus.