Two points here. If the US markets fail to recover and go down...

Two points here. If the US markets fail to recover and go down further in a big way, they have no option but to ease a lot more to counter the effect of a recession/depression - inflation would be dead. If the markets rally good for many months, then they will raise rates as usual to counter inflation. In other words, rates follow the markets, not the other way. Look at the curretn T-bill rate - now below 1%. This means they have around 150 bps of easing to go, unless they rally back to where they were in Jan, namely over 3%.