The worst-case scenario occurs if 10-year interest rates exceed 4.5%

Read: The Creator Of The Bond Volatility Index Reveals When The Fed Will Finally Lose Control

Surely at some point there comes a time when not even the Fed can print its way to prosperity. As it turns out, such a point does exist according to Bassman, who says a worst-case scenario, "has to include a situation where the FED can no longer hold back the tides; and I will volunteer this occurs if interest rates significantly increase, perhaps above 4.5%" as a result of the massive debt load carried by the system. As Bassman notes, the old rule is that the T10yr rate should tend toward nominal GDP. As such, a real GDP at 2.0% plus an inflation of 2.5% should lead to a T10yr rate of 4.5%.

So, the Fed CAN print its way to prosperity so long as the 10yr does not reach 4.5%.  Currently it is at 0.66%.

What happens if the danger zone is reached?  Can't it just raise interest rates and coordinate with Congress to raise taxes to suck money out of the system?

So print away.  Just give everyone a million dollars and see what happens.