Two-state proponents, while conceding that there is no way to know for sure how the Palestinians would react, say a sovereignty push would almost certainly lead to a nightmare of one kind or another for Israel, like a rise in violence and international condemnation.

The incremental entrenchment of Jewish settlements on Palestinian land is often called “creeping annexation.” And until now it has occurred slowly enough, and piecemeal enough, to let supporters of a two-state solution reassure themselves that such steps could still be undone or accounted for in future negotiations.

Applying sovereignty, by contrast, would be all but irreversible.

Whether accomplished quickly or by degrees, it is tantamount to annexation, and it would break with a quarter-century-old agreement, under the Oslo accords, that the status quo between Israel and the Palestinians must not be altered except through negotiations.

For years, Mr. Netanyahu positioned himself as a check on both sides in the debate. He placed himself to the right of supporters of a two-state solution on the one hand, and to the left of those who want to annex the West Bank and see a so-called Greater Israel fulfill the Zionist dream of a Jewish state from the Jordan River to the Mediterranean.

Those Israelis were once marginalized as part of the right-wing fringe. But with fewer than half of Israelis still supporting a two-state solution, it is the peace camp that is now out of step with the majority of society. A fast-growing sovereignty movement, called Ribonut in Hebrew, has not only achieved political acceptability but has overtaken much of the powerful Israeli right wing.