Is it logical to think of the U.S. holding rates steady against the backdrop of declining interest rates by foreign central banks as an effective rate hike here in the U.S.?
No. What is important is the interest rates that would exist in the US without Fed intervention. And with price inflation starting to accelerate in the US, the slower the Fed moves to raise rates the more damaging it will be in terms of price inflation and distortions in the capital-consumption structure of the economy.
There is no such thing as an effective rate in terms of these factors just because other central bank are keeping rates at even more insane low level.