I don't see why it HAS to be impossible that there could be a single joint state of Israel-Palestine, ruled by political parties composed of Jews and Arabs together with Jerusalem as the capital of a unified state. The main obstacles are the people on either side who absolutely refuse anything less than total victory for their side.
The Israeli parliament does have one kinda legit argument against this, namely that if all the Palestinians in "their" territory had weight in the Israeli government, they'd vastly outnumber the Israelis, and we can be sure that wouldn't end well either. So they pretty much have to pretend that Palestine is actually a separate country squatting on their land, because if they admitted Palestine into its governance and wanted to protect their control over the process, then it would be abundantly obvious how screwed up the situation they've engineered is.
Yeah, kinda like how the white South Africans couldn't possibly let the blacks vote because there were so many more of them, and it would end in mass slaughter of the whites. Except that it didn't.
I mean, I know that *is* the argument that people use in the Knesset. I'm just saying it's not necessarily a given that Palestinian majority would be a horrible thing.
Sinn Fein got brought into the political system in Northern Ireland. There was no genocide of Protestants.
The ANC got brought into the political system in South Africa. There was no genocide of white South Africans.
A Palestinian majority brought into the Israeli political system doesn't inherently mean a genocide of Jewish Israelis.
At the end of the days, politics is politics. Give your constituency what they want, they'll vote for you. The vast majority of Palestinians want food, water, electricity, a decent place to live, and a job. If an Israeli Jewish politician can offer them that (and they have good reason to believe him/her), they'll vote for him.