A far more important reason is the growing fear of Israel's isolation in the world.
Netanyahu is now engaged in a ferocious fight against President Obama. He opposes the Iranian deal with everything he has. But this deal is also underwritten by the European Union, Germany, France, Russia and China. Netanyahu against the entire world.
Netanyahu has no illusions. There are hundreds of ways Obama and the European Union can punish Netanyahu. Israel is almost totally dependent on the US as far as weapons are concerned. It needs the US veto in the UN, and US subsidies also come in handy. The Israeli economy is also heavily dependent on European markets.
In this situation, it would be nice to have Isaac Herzog on board. He is the ultimate fig-leaf, a nice liberal leftist as foreign minister, son of a president, grandson of an Irish chief rabbi, well mannered, European looking, English speaking. He would pacify the fears of the world's foreign ministers, cushion Netanyahu's rough edges, prevent diplomatic crises.
Labor in the government would also block the deluge of anti-democratic bills which accumulated in the last Knesset. It would also halt the planned onslaught on the Supreme Court, Israel's last bastion against the barbarians. The leading group of Likud extremists make no secret of their intention to castrate the Court and to enact the bills they hold in store.
Labor might also mitigate the economic policies of Likud, popularly known as "swinish capitalism," which have made the poor poorer and the ultra-rich even ultra-richer. Housing might become affordable again, the decline of the health and education systems mighty be halted.
The prospect of becoming ministers again makes the mouths of some Labor functionaries water. One of them, Eytan Kabel, a close ally of Herzog, has already published a statement totally supporting Netanyahu's Iran policy, raising many knowing eyebrows.
The Labor Party has yet to take a critical position towards Netanyahu's Iranian stand. It only criticizes -- halfheartedly, if not quarterheartedly -- the Prime Minister's attacks on Obama.
ON THE other side, what's so wrong about a National Unity Government?
Well, first of all, it leaves the country without an effective opposition.
In order to function, democracy needs an opposition that develops alternative policies and provides a choice at the next elections. If all the major parties are in the government, what alternative forces and ideas can provide the necessary choice?
A cynic may remark here that the Labor Party was not much of an opposition anyway. It supported last year's superfluous Gaza War with all its atrocities. Its ally, Tzipi Livni, has dragged the Palestinian negotiations on and on without coming an inch nearer to peace. Labor's opposition to the rightist economic policies was feeble.
Truth is, Labor is not built for opposition. It was in power for 44 consecutive years (from 1933 to 1977, first in the Zionist Organization and then in the new state). To be "governmental" is deeply ingrained in its nature. Even under Likud governments, Labor was never a determined and effective opposition.
But for Leftists, the main objection to a Unity Government is exactly what may induce Netanyahu to install it: because it provides the big fig leaf.
Labor in the government will blunt all foreign criticism of Netanyahu's policies and actions. Israeli Leftists, who despairingly pray for foreign pressure on Israel, such as an all-inclusive boycott (BDS) and pro-Palestinian UN resolutions, will be disappointed. To get such a campaign moving, you need a far-right government in Jerusalem.
Under the National Unity umbrella, Netanyahu can continue to enlarge the settlements, sabotage the Palestinian Authority, conduct endless negotiations that lead nowhere, even make war from time to time.
(Note: You can view every article as one long page if you sign up as an Advocate Member, or higher).