The recent State legislative seat balance of power is below.
It is noteworthy that Democrats have not picked up a great deal of legislative seats in the last couple of cycles, even though they did well nationally.
That could portend a large wave of seats if the Democrats have a large national wave this year.
Chambers in play, per Cook Political:
Alaska House: It is not the partisan majority, which will remain Republican, rather it is a very organized effort by Republicans to oust moderate Republicans who have been allying with Democrats to control the chamber as a coalition.
Arizona: Democrats have an excellent opportunity to flip both Houses of the Legislature.
Florida: The State Senate is in play, but it will be difficult for Democrats to flip.
Georgia: Both Houses of the Legislature are in play, but again, it will be difficult for Democrats to flip either one.
Iowa: The State House is in play but will again be difficult for Democrats to flip.
Maine: The State Senate is in play, but in this election cycle, unlikely Republicans can flip it.
Michigan: Democrats have a good chance to flip the State House.
Minnesota: Democrats have an excellent chance to flip the State Senate.
New Hampshire: Republicans have an outside chance at the State Senate.
North Carolina: Democrats have a small chance at flipping either or both chambers.
Pennsylvania: Democrats have a small chance at flipping either or both chambers, smaller than in North Carolina.
Texas: Democrats have an outside shot at flipping the State House.
State Legislative seats balance of power since 2009.
(Note: Nevada’s single legislative chamber is included in the cumulative State Senate total and its 49 members count as others since they are officially elected on a non-partisan basis.)
2009: (reflects Obama’s 1st election, significant Democrat wave)
Senate: 1971 total seats, 1024 Democrat, 889 Republican, 52 Other, 6 Vacant
House: 5411 total seats, 3058 Democrat, 2334 Republican, 17 Other, 2 Vacant
2011: (reflects the broader electoral kickback against Democrats in 2010)
Senate: 1971 total seats, 888 Democrat, 1027 Republican, 54 Other, 2 Vacant
House: 5411 total seats, 2468 Democrat, 2917 Republican, 19 Other, 3 Vacant, 4 Undecided
2013: (reflects Obama’s 2nd election, a very weak move towards Democrats)
Senate: 1972 total seats, 889 Democrat, 1022 Republican, 55 Other, 6 Vacant
House: 5411 total seats, 2592 Democrat, 2791 Republican, 24 Other, 4 Vacant
2015 (reflects the strong 6th year Republican wave)
Senate: 1972 total seats, 828 Democrat, 1087 Republican, 52 Other, 4 Vacant, 1 Undecided
House: 5411 total seats, 2342 Democrat, 3039 Republican, 22 Other, 2 Vacant, 6 Undecided
2017 (Trump’s election, modest Republican wave)
Senate: 1972 total seats, 796 Democrat, 1124 Republican, 52 Other
House: 5411 total seats, 2332 Democrat, 3055 Republican, 22 Other, 2 Vacant
2019/20 (Strong Democrat wave, also includes 2019 odd year election)
Senate: 1972 total seats, 856 Democrat, 1055 Republican, 53 Other, 8 Vacant
House: 5411 total seats, 2586 Democrat, 2779 Republican, 28 Other, 18 Vacant