Whether Yitzchak knew it was Yaakov he was blessing or he thought it was Eisav, is irrelevant to the other bracha he gave Yaakov at the end of the sedra. And Yitzchak called to Yaakov and he blessed him... May G-d bless you and cause you to be fruitful and multiply and become a nation... May He give you the Blessing of Avraham to you and your descendants with you to acquire your Land that G-d gave to Avraham. Earlier, the Torah made it clear that it would be through Yitzchak that the Heritage and Legacy of Avraham would pass, as would the Land of Israel. And NOT through Yishmael. And NOT through Eisav. If these statements are politically incorrect in some circles, it is those circles that need fixing, not the statements and not the Torah from which they come. Eisav was given land elsewhere; not here.
And when anyone says: Get real, Bush has an agenda and the UN and EC have their agendas and the Arabs have theirs... The answer is, this is real. The Torah is real. It doesn't become defunct because people say this and claim that. Whatever happens, wherever we go from here, this has to be our starting point, our basis, our truth.
But we also must see the blessing Yizchak gave Eisav, when he knew exactly what was going on. That bracha contains a warning to us, the descendants of Yaakov, the Jewish People. If and when we disregard the Torah, its teachings, its mitzvot, its values, then we can lose the high ground position, so to speak, and Eisav can and will take advantage of that situation. When we strengthen our commitment to Torah and Mitzvot and spread that to our fellow Jews, then we will see the fruition of all the Blessings.