Yom Ha'atzmaut is political, they say, and thus has no place in our religious liturgy.
They are half right: Yom Ha'atzmaut is indeed political.
Furthermore, the story of Avraham is political.
The stories of Yitzhak, Yaakov and Yosef are political.
The story of Moshe is certainly political - Pesach is political.
The books of Bamidbar and Devarim are political.
Sefer Yehoshua is political, as are Shoftim, Shmuel and Melachim.
The latter prophets were political too.
The first Rashi on the Torah is political. So is the first Ramban.
Rosh Hashana is political. (Read the middle brachot of the Amidah.)
Purim is political.
Chanukah is political.
Tisha B'Av is political. As are Shiva Asar B'Tamuz, Asarah B'Tevet and Tzom Gedaliah.
The books of Ezra and Daniel are political.
The benching is political. So is the daily Amidah.
The rabbis of the Talmud were political. Some of them were even politicians.
Bar Kochba and Rabbi Akiva were political.
The mission of the Jewish people, from Abraham on, has been to develop a sovereign nation in its own land which sets an example for mankind - a light unto the nations - by worshiping God according to the Torah. Our story has been one of steps forward towards that goal - events of redemption - and of unfortunate failures and defeats - events of destruction and exile.
Yom Ha'atzmaut celebrates the most significant accomplishment towards our national mission in some 2000 years: reestablishing Jewish sovereignty over our homeland, a necessary prerequisite for the possible fulfillment of our national destiny. Its achievement on the heels of one of our greatest tragedies in history made it all the more miraculous.
We don't know what the state will bring in the long run. Will we fulfill our highest visions, or once again, God forbid, lapse into failure and ruin? We can't know that, any more than newlyweds can know whether their marriage will thrive or wither. That's no reason not to celebrate the achievement and thank God for making it possible.
Yom Ha'atzmaut is political. It is a major milestone in the achievement of our timeless national purpose as set out in the Torah. To leave it out of our religious liturgy would be a sign of ingratitude and historical blindness.