The last three generic ballot polls don't look too good for Democrats

Of course... isn't this all a matter of timing? Which polls come out at what time?

Polling Data

Poll	Date	Sample	Republicans (R)	Democrats (D)	Spread
Average	7/5 - 7/22	--	44.9	42.4	Republicans +6.3
Trafalgar Group (R)	7/20 - 7/22	1085 LV	48	40	Republicans +8
Emerson	7/19 - 7/20	1078 RV	45	44	Republicans +1
Rasmussen Reports	7/17 - 7/21	2500 LV	49	39	Republicans +10

A week or so there will be a couple of polls (YouGov and Politico) that have consistently shown a small Democratic lead and everyone on the left will jump up and claim that the momentum has shifted. The reality is that there has not been much of a shift in all of this for some time. 

Every poll Politico has come out with over the past several months has shown Democrats ahead (or in one case tied). YouGov has been similarly more favorable to Democrats. Meanwhile, Trafalgar and Rasmussen have been consistently showing huge GOP advantages. When those two come out at the same time and you toss in another poll (like Emerson) that shows a GOP lead, well it can start to look like a whole scale wipe out. 

But who is accurate and who isn't? 

What I can tell you is that in 2020 YouGov overstated Democratic support by about seven points (yes you read that correct - they were off by seven point). Politico overstated Democratic support by four points. Rasmussen has both overstated and understated GOP support over the years, but has been closer than most.  Emerson (showing a small GOP lead) has been pretty dang close the past couple of election. This is the first time I have seen Trafalgar do generic ballot polling.

The one thing to keep in mind here folks is the big liberal state problem with these polls. These are national polls which include huge (but irrelevant) amounts of overwhelming support from places like California & New York. It never matters if someone wins by two points or twenty. Because of these overwhelming liberal states, traditionally the "battleground" districts will trend 2-3 points further towards the GOP than national polls do. This has allowed the GOP in the past to pick up seats even as they lose the overall popular congressional vote. Moreover, the year that they picked up 63 seats (2010) they got just over 51% of the overall vote. 

Either way... Democrats are in trouble if the GOP comes out with any sort of popular vote win. 

So if you accept the premise that the RCP average of two and a half point is probably pretty solid, that would suggest that the battleground districts are probably more like a five point lead for the GOP. This would also be consistent with some specific battleground polling that has been done. A four or five point advantage in the battleground districts  would not bode well for Democrats and probably would suggest a much larger GOP gain than some are expecting. 

Time will tell...