In dealing with Isaiah there is contextual reason to interpret reject the idea that the passage refers to the nation state that was established in 1948. Paul states that not all of Israel is Israel. And further defines what He means by going on to talk about the faithful.
"In dealing with Isaiah there is contextual reason to interpret reject the idea that the passage refers to the nation state that was established in 1948"
Your quote here, if not referring to Israeli state of 1948, then 'who', 'what', 'when', and 'where' are the peoples referred to as Israel in the passage? The passages refer to Israel.
"Paul states that not all of Israel is Israel. And further defines what He means by going on to talk about the faithful"
Is this the same Israel that is recorded at Isaiah 45? Some people claim Paul is the Apostle to the Gentiles and this further confounds the matter of the 4 w's as above. It appears to me that you may be referring to what is known to some as 'Spiritual' Israel. If that is the case would you see Pauls' statements of "Israel" as distinct from the "Israel" of Isaiah 45?