HaKatan: See, that’s the thing I wonder about gedolim: everyone says that according to OUR gedolim, something is obviously true. The next poster then (t)rolls along and it’s batuach shelo! Because OUR gedolim say so! (And just BTW, mods, why was the record of that other gedolim thread erased from living memory? I was getting really interesting and occasionally pretty helpful responses to my questions.)
I’ve had teachers whom I’ve liked and trusted say that Zionistic wars were milchemes mitzvah, and I’ve had other teachers, whom I’ve liked and trusted equally, say the opposite. The former category spans the gamut from chassidishe-rebbishe-Israeli rebbetzin (you’d know the name if you heard it) to ultra-shtark dati leumi yoredet who did sherut leumi to regular, JPF American. The latter category- actually, the range is approximately the same (though the ultra-shtark dati leumi yoredet really just said that there are different opinions in this case). They’re not poskim- but ask any of them, and these uber-intelligent, ginormously spiritual women can reel you off perek and pasuk as a proof for what they believe.
This is partly because there are different definitions of Zionism, and partly because there is really no concrete answer, unless you believe that only your mekor is right and everyone else is wrong, which you will find difficult to convince people of.