In his article, “2022 House Overview: Still a GOP Advantage, but Redistricting Looks Like a Wash,” at The Cook Political Report, David Wasserman writes:

The surprising good news for Democrats: on the current trajectory, there will be a few more Biden-won districts after redistricting than there are now — producing a congressional map slightly less biased in the GOP’s favor than the last decade’s. The bad news for Democrats: if President Biden’s approval ratings are still mired in the low-to-mid 40s in November, that won’t be enough to save their razor-thin House majority (currently 221 to 212 seats).

The start of 2022 is an ideal time to take stock of the nation’s cartographic makeover. New district lines are either complete or are awaiting certification in 34 states totaling 293 seats — more than two-thirds of the House (this includes the six states with only one seat).

A Cook Political Report with Amy Walter analysis finds that in the completed states, Biden would have carried 161 of 293 districts over Donald Trump in 2020, an uptick from 157 of 292 districts in those states under the current lines (nationwide, Biden carried 224 of 435 seats). And if Democrats were to aggressively gerrymander New York or courts strike down GOP-drawn maps in North Carolina and/or Ohio, the outlook would get even better for Democrats.

However, the partisan distribution of seats before/after redistricting is only one way to gauge the process. Because Democrats currently possess the lion’s share of marginal seats, estimating the practical effect of new lines in 2022 still points towards a wash or a slight GOP gain.

Wasserman notes further that “so far Republicans have only gone on offense in Georgia, North Carolina and Ohio — all of which face court scrutiny.” Also,

Meanwhile, Democrats unabashedly gerrymandered Illinois, New Mexico and Oregon. They scored highly favorable maps from commissions in California and New Jersey, and to a lesser extent Michigan. Republicans’ only mild commission “wins?” Arizona and Montana. And five states where the GOP had exclusive authority back in 2011 — Louisiana, Michigan, Pennsylvania, Virginia and Wisconsin — are now under split or commission control.

Even though Biden carried 224 of 435 seats in 2020, the current House map has a slight pro-GOP bias: the median district, held by Democratic Rep. Lauren Underwood (IL-14), voted for Biden by 2.4 points, two points to the right of his 4.4 point national popular vote margin. Nationally, according to the PVI, there are 230 districts that lean more Republican than the nation as a whole, compared to 205 districts that lean more Democratic.

So far, completed states look surprisingly rosy for Democrats. There are 15 seats that have “flipped” from GOP-leaning to Democratic-leaning: CA-13, CA-45, GA-07, IL-13, IL-14, IL-17, MI-03, MI-11, NV-03, NJ-03, NJ-05, NJ-11, NM-02, OR-04 and VA-07. By contrast, there are only nine seats that have “flipped” the other way: AZ-06, CA-40, GA-06, MI-08, MI-10, NJ-07, NC-02, NC-07 and OH-09. That’s a net gain of six Democratic-leaning seats.

‘However,” Wasserman adds, ” the oldest rule in the book is that you can’t gain a seat you already hold. Looking under the hood, Democrats already hold 11 of the 15 “newly Democratic-leaning” seats, meaning only four are pickup opportunities. By contrast, Republicans only hold one of the nine “newly GOP-leaning” seats, giving them eight map-enhanced pickup opportunities – twice as many as Democrats. At least in 2022, that’s a GOP advantage.”

Wasserman notes, “It’s still too early to render a final verdict on redistricting. There are still 16 states that aren’t complete (or near-complete), not counting the handful of states with high-stakes litigation pending. Republicans could still target Democratic seats in Florida, Tennessee and New Hampshire, and far less likely in Kansas, Kentucky and Missouri. Democrats could offset all of that in New York.” He warns, “Some of the narrowly Biden-won new seats where Democrats are especially vulnerable are AZ-06, IL-17, MI-07, MI-08, NV-01, NV-03, NV-04, NJ-07, NC-02, VA-02, VA-07 and WA-08. And, this list is certain to expand as more states finish maps….Adding to Democrats’ challenge: retirements. At this writing, there are 24 Democrats not seeking reelection in 2022, including 11 from potentially vulnerable districts. The retirements of Reps. Stephanie Murphy (FL-07), Cheri Bustos (IL-17), G.K. Butterfield (NC-02) and Ron Kind (WI-03) are the most problematic. By contrast, there are only 11 Republicans heading for the exits, none of whom were truly vulnerable under their current lines.”

In his concluding paragraphs, Wasserman explains, “Democrats began the cycle with virtually no margin for error, and the drag from Biden’s disapproval – inextricably linked to retirements and GOP recruitment/fundraising — long ago overtook redistricting as the leading threat to Democrats’ majority. Their only hope of holding on involves not only key map battles in New York, North Carolina and Ohio breaking their way but the president’s approval rating rebounding much closer to 50 percent.”