On the evening of March 16, Ohio state officials said polling places would not open on March 17, which is Ohio’s primary day for president and all other partisan office. However, elections are proceeding on March 17 in Arizona, Florida, and Illinois. Officials in those states say if the primaries were postponed on March 17, it might be even more difficult to hold them in April, May, or June. The major party national conventions are in July and August.

The Ohio Supreme Court made the Ohio action possible. Here is the one-page order in State ex rel Speweik v Wood County, 2020-0382, issued early on March 17.

The petition deadline in Ohio for non-presidential independent candidates is primary day. This deadline already was constitutionally shaky, because the petition deadline for newly-qualifying parties is not until July of election years (regardless of the date of the primary, which varies from March in presidential years to May in other years). If the primary is not being held on March 17, it seems to follow logically that the petition deadline is not on March 17 either. UPDATE: the Secretary of State says the new primary day is June 2. See his website here.