Just to add a few comments: Way before Herzl, there was Rav Mohilever, R’Zvi Hirsch Kalisher, the Netziv, Moshe Montefiore and ,of course, talmidei HaGro and HaBesht. So, Zionism, as a return to Eretz Yisroel existed for decades and centuries before Herzl. What Herzl did was to make this a mission and to champion a place for Jews, who were persecuted everywhere. I daresay that Herzl learned from the religious Rabbis who came before him!
What was different in the late nineteenth century was the wave of nationalism that was prevalent in all of Europe (Greece, Italy, Serbia,Finland,etc..) and so Zionism took the form of a national purpose. unlike some of the Russian maskilim (Achad Hoam and others), Herzl had no notion of religion and would not make any statement on this. The tragedy for Jewry was that the Orthodox leaders in Europe were fighting a war against the maskilim and reform and were not able to differentiate them from Zionists. If the orthodox establishment in Europe would have understood the dangers lurking ahead, been able to separate the anti- religious crowd from the real zionists and galvanized the masses to make alyah, history would have been different. Rav Kook’s contribution was to highlight the importance of Eretz Yisroel in Judaism, something that had ben lost since the churban.So, there were grievious errors all around and European jewry paid the price in WWII.