Florida lawmakers are scheduled to begin a special legislative session on April 28 to consider congressional redistricting, making the state the latest to take up the redrawing of U.S. House districts ahead of the midterm elections. The Florida state constitution prohibits drawing districts with the intent to favor or disfavor a political party or incumbent.

Voting districts are typically redrawn once a decade after each census, but since last summer, six states have adopted new U.S. House maps outside the usual cycle. Last year, President Donald Trump urged Texas Republicans to redraw House districts to give the GOP a partisan advantage in the midterm elections, and California Democrats launched their own mid-decade redistricting efforts following Texas Republicans' actions.

Texas Governor Greg Abbott signed a revised U.S. House map into law in August that could help Republicans win five additional seats. The U.S. Supreme Court in December stayed a lower-court ruling blocking the new Texas map, allowing the districts to be used in this year's elections. California voters in November approved revised districts drawn by the Democratic-led Legislature that could help Democrats win five additional seats, and the Supreme Court in February allowed those maps to stand by denying an appeal from Republicans and the Department of Justice.

The Republican-led North Carolina General Assembly gave final approval in October to revised districts that could help Republicans win an additional seat, and a federal court panel in November denied a request to block those maps. Missouri Governor Mike Kehoe signed a revised map into law in September that could help Republicans win an additional seat. The Missouri Supreme Court rejected a lawsuit claiming mid-decade redistricting is illegal but is scheduled to hear arguments in May on whether the new districts violate compactness requirements.

Virginia voters are voting on a constitutional amendment on April 16 to allow mid-decade redistricting. Virginia's Democratic-led General Assembly passed a new U.S. House map that could help Democrats win up to four additional seats. The Virginia Supreme Court ruled the referendum can proceed but has yet to rule on its legality, as it considers an appeal of a Tazewell County judge's ruling that the amendment is invalid.

Republicans believe they could win nine additional seats in states where they have redrawn congressional districts, while Democrats believe they could gain six seats because of redistricting. Democrats need a small number of additional seats in the November midterm election to win a majority in the House of Representatives, which would allow them to block Trump's legislative agenda.