Even the Ramban, who lists conquering Eretz Yisroel as one of the 613 commandments, would not obligate conquest nowadays. Since the mitzvah is conquering the land and it doesn't apply nowadays, we aren’t really doing the mitzvah when we live in Eretz Yisroel. What we are doing is preparation for the mitzvah, just like baking matza is a preparation for the mitzvah of eating matzah. (Yeshuos Malko, Yoreh Deah 66)