The justification for the creation AND EXPANSION of the state of Israel is given only by a certain stripe of zionist--with the support of the US . In this sense I don't see how it's possible to separate political zionism from the state of Israel. Zionism is not an ethnic category it is an ideology with a set number of followers. No DNA is at issue here (except from the point of view of the zionist--which is why some have referred to the state of Israel as Hitler's last wish.)
Let's also be careful about the flavor of Israeli nationalism: it is not originally based on the Jewish posession of land it is based on the jewish claim to a certain land...given by the Bible to those that have a certain blood running through their veins.
There are many kinds of "nationalisms": there is the nationalism, say, of an occupied people fighting for its right to self determination and then there is the nationalism of those countries who are claiming the right to oppress others. Israeli nationalism is actually the latter disguising itself as the former. For more details, please read the history. The idea of Israeli colonizers bringing enlightenment to arab cockroaches is explicit in the writings of many of the founding fathers of Israel.
Joanna Bujes