In ideal world international peacekeeping forces would be deployed in Gaza. The peace and two state solution could only be enforced by imposing severe sanctions on Israel including possibility of aerial NATO strikes like in the former Yugoslavia.
Is two-state solution possible? Just look at the map of the territories under palestinian control, they're bantustans. Israel/Palestine is factually one state, which simply doesn't accept half of its population as citizens. You could also say that "two-state solution" has been tried in 1948, but (for whatever reasons) didn't work out. So support for 2-state is just a form of delaying the inevitable. I am now firm bel…
The Arab world overwhelmingly rejected the UN Partition Plan in principle, which led directly to the 1948 Palestine war and the first Arab-Israeli war. Likewise, the signing of the Oslo Accords (and the rejection of those accords by Hamas, PIJ and other factions within the PLO) led directly to the Second Intifada. Most of the Arab world has now conceded that Israel isn't going anywhere and huge steps have been made in normalising Arab-Israeli relations, but Palestinian politics is still dominated by a fundamentally futile anti-Zionist absolutism.
A credible option of full statehood and international recognition has been on the table for nearly eighty years, but Palestinians have consistently failed to establish a workable consensus on taking up that option. The PLO's intransigence has alienated most of their allies in the region, primarily because they instigated civil wars in both Jordan (1970) and Lebanon (1975).
A one-state solution is no solution at all while there remain extremists on both sides who are simply unwilling to coexist; unless Israel can reign in the religious right and the Palestinians can establish a political consensus in favour of coexistence, it's a straightforward path to war. There's no "poetic justice" in making people who hate each other live together, just an inevitable perpetuation of bloodshed.
The political debates about land rights are intractably complex, but the fundamental realpolitik question is about how much the Palestinians are willing to suffer for the principle of "from the river to the sea". Israel is militarily dominant and is likely to remain so regardless of how much international pressure is brought to bear. In simple practical terms, the ball is in the Palestinian court and it is for them to decide whether to seriously engage in a two (or three) state solution with international support, or whether to continue pursuing an unwinnable conflict. A post-Netanyahu Israel is highly likely to support a serious two-state solution, but simply isn't going to accept a one-state solution; even if you believe a one-state solution to be the only just outcome, it isn't a workable outcome.