Florida Gov. Ron DeSantis (R) said Monday that he signed into law a new set of congressional lines that could net his party up to four House seats in November.

The Supreme Court’s 6-3 ruling last week in Louisiana v. Callais provided a predictable snapshot of how the justices line up in some of the most crucial cases.

Equal Ground Education Fund, a Black-led organization that works to increase Black political power in Florida, filed a 71-page lawsuit in the Second Judicial Circuit in Leon County on behalf of 18 ind...