Avi K- Zionism is more than political movement and has been since 1948. The very basis of the government and legal system are based on Zionism which has its own political parties. Yes, there is religious representation as well, but there are limits to their power. I don’t think they would be able to change the nature of the government of Israel into a theocracy based on the Talmud and Shulchan Aruch even if they were in power.
My personal opinion, is that the State of Israel as it stands is a secular state (with some significant Jewish influences). As it is a secular state, I am hesitant to say that the State of Israel is synonymous with Jewish Sovereignty over the Land of Israel. (I guess a question can be made how to compare the current secular State of Israel with the idol worshiping Malchei Yisroel of Tanach- was that not considered Jewish Sovereignty either?)
But, the secular State of Israel offers more opportunities for Yishuv Eretz Yisroel (Right of Return), more governmental funds towards Torah and maintaining holy areas, and more manpower to defending Eretz Yisroel and Jewish People in Eretz Yisroel and around the world. Not to mention the fact that Giyur and Marriage run through the State Rabbinate limits the existence of intermarriage even among completely irreligious Jews. No other secular government would offer that to Klal Yisorel and that’s something we all need to appreciate.