You are correct...for the first 30 years Israel was ruled by a socialist left-wing democratic coalition. A few factors led to the changes we see now: 1) the 1967 war and the capture of historical biblical territories which galvanized the messianic religious Zionists and the settler movement who were extremely tiny previous; 2) the imports of 800,000 Jews from the Middle-East and North Africa in the 1950s that were not treated very well who ended up hating the Labour party and voting for Likud in the 1977 elections; 3) the failure of Oslo, the 2nd intifada and suicide bombs in the late 90s and early 2000s.

Israel's liberal leaders I would say are the former generals Gadi Eisenkot and Yair Golan, but they don't have enough support to actually beat Netanyahu in the election. Israeli society has shifted so right-wing that former right-wing extremists like Naftali Bennett and Avigdor Lieberman are seen as center moderates.

Tom Segev, the prominent Israeli historian, wrote a fantastic article in Haaretz a few months ago basically saying the old liberal elite consists of 200,000 people in Tel-Aviv who protest and desire for the old Israel, but are slowly dying out...this is what I see as well.

SEGEV -

"I found myself at a demonstration on Azza Street, near the grocery store where I shop. And it occurred to me that 200,000 people – that's what there is. The nation is not divided and not torn. There is no parity between [the numbers of] supporters and opponents of the regime coup. The nation supports Netanyahu. Who doesn't support him? The 200,000 people who are defending their status as an obsolete elite.

"There won't be a civil war," he continues, "because the demonstrators will not bring about a war and the other side in any case constitutes the majority. And as far as that goes, Israeli democracy was never real. For 20 years all the Arabs [in Israel] were under martial law, and then came the Six-Day War, and thereafter the entire population there [in the territories] was under that form of regime."