“Victory over Covid has been clearly their only hope in the midterms for sometime now.”
It seems to me that the (real) decline in COVID is pretty much baked into the cake by the very high levels of accumulated immunity, and that the Democrats in Government are further putting their thumbs on the scale to accelerate the reported declines.
Conventional wisdom now is that the State of the Union Address, scheduled for March 1st, will likely be the declaration of victory, and signal a raft of re-opening policies, to give the economy some boost going into the mid-terms as well.
I don’t think immunity is cumulative. If there is immunity gathered in August of last year to Delta, it will be 6 months old about now and thus begin to crash in effectiveness.
Keep an eye on the monthly study updates from the REACT people in London (Imperial Univ or something). Their most recent report said about 5-10% of current cases had documented pre-infections of over 1 month old. Get to 6 or 8 and dying starts.
And this is purely age. Not variant, the next one of which is due about now.