The chareidi MK’s have to take an oath of allegiance to the State of Israel:
“I pledge myself to bear allegiance to the State of Israel and faithfully to discharge my mandate in the Knesset.”
And the rabbonim who support them don’t seem to have a problem with this. I realize it’s not the same as the declaration on the Zionist elections page, but it’s still an issue if you’re anti-medinah.