I can't promise any predictions or comprehensive, definitive analysis here; I'm not a political consultant (thank God!) But it seems like the GOP is trying to muddle its way as the minority opposition party in the aftermath of the quixotic 2020 campaign where Trump was defeated for reelection but the Dems underperformed expectations, held on to the House by a razor-thin margin and regaining the Senate but not gaining an expected majority.
As we head into next year's mid-terms, the GOP Senate is clearly playing defense, defending 20 of 34 seats. Moreover, 5, maybe more of those 20 seats are open (meaning the near-lock of incumbent retention). I think the Dems have shots of converting WI, NC, OH, PA and MO. The GOP's best shots include the recent flips of AZ and GA and perhaps NH, NV, and CO (I think easier said than done, but turnout of Dems tends to be softer during midterms). Objectively, you have to like the Dems chances: so far none of their 20 seats are open, and I haven't heard of strong Republican candidates emerging to flip those states, never mind retaining tough open seats in PA and NC. (Former pro athlete Herschel Walker could be a contender in GA, but I haven't seen any poll data.) I think Larry Hogan would make a credible challenge for Van Hollen's seat, but I don't see him resigning from his position as governor to do so, and I think his eye is on the 2024 GOP Presidential primary. We still don't know whether Johnson (WI), Grassley (IA) or Murkowski (AK) are running for reelection, although I expect the Dems' best chance is WI. I do think Trump's influence in Senate primaries could be a problem for the GOP's already decidedly uphill chances to regain the Senate. Still, the average loss of Senate seats in a midterm is 4 in favor of the POTUS' opposition.
The prospects for the GOP are much brighter in the House, with red states probably getting an advantage in new Congressional districts after the Census, but blue states could offset that in redistricting (e.g., Illinois is rumored to be targeting Kinzinger's seat). Currently the Dems have an advantage of about 8 seats; that means if the GOP can flip a majority of those, they can regain control. The average loss of a President's party is 26 seats, so clearly the trend for GOP recapture of the House, while not a lock, is very favorable.
To a large extent, the Dems are acutely aware that their majority may be fleeting in nature, which is perhaps why you are seeing an emphasis on pushing big spending items (including the massive $3.5 trillion domestic spending initiative), voting rights, and pushes for ending the Senate filibuster. Naturally these votes put pressure on vulnerable Dems in purple and red states on the hot seat.
Obviously, Dem chances in the midterms heavily rely on Biden's approvals, and it is not lost on the Dems how a reasonably popular Obama lost the House in his first mid-term. I don't see anything comparable to the Tea Party rebellion spawned by the morally hazardous government mortgage bailout legislation. It does appear like the Biden honeymoon is over in large part attributed to:
- the Delta wave of coronavirus, with cases, hospitalizations and deaths in numbers we haven't seen since January, even as over half of Americans are fully vaccinated and over 72% of adults at least partially vaccinated. There has been a backlash against Biden policies pushing for vaccine mandates for government employees and universal masking.
- some economic issues, particularly warning signs of (temporary?) food and energy inflation; this includes worries of Fed changes in policy possibly triggering a recession.
- the messy ending of our withdrawal from Afghanistan.
- continued issues at the Southern border
