zahavasdad: Saying you won’t be in a coalition with someone means you won’t join the coalition unless your conditions are met. That’s how it works in a parliamentary system, in Israel and everywhere else. The problem for Herzog is that Lapid refuses to sit with the hareidim, or more specifically (since money isn’t the issue this year), Lapid insists on conscripting hareidim (“share the burden”) and the hareidim refuse to be conscripting (alledgedly about learning Torah, but many hareidim are anti-zionist holding that Medinat Yisrael is guilty of waging an illegal war to evict the goyim for Eretz Yisrael). Netanyahu has a similar problem with most of his probably coalition partners.
The solution probably would involve ending conscription, which would be revolutionary in the State of Israel.