That’s a point that Israel’s restless critics could stand to learn. On Friday, Palestinians in Gaza returned for the fourth time to the border fence with Israel, in protests promoted by Hamas. The explicit purpose of Hamas leaders is to breach the fence and march on Jerusalem. Israel cannot possibly allow this — doing so would create a precedent that would encourage similar protests, and more death, along all of Israel’s borders — and has repeatedly used deadly force to counter it.

The armchair corporals of Western punditry think this is excessive. It would be helpful if they could suggest alternative military tactics to an Israeli government dealing with an urgent crisis against an adversary sworn to its destruction. They don’t.

It would also be helpful if they could explain how they can insist on Israel’s retreat to the 1967 borders and then scold Israel when it defends those borders. They can’t. If the armchair corporals want to persist in demands for withdrawals that for 25 years have led to more Palestinian violence, not less, the least they can do is be ferocious in defense of Israel’s inarguable sovereignty. Somehow they almost never are.

Israel’s 70th anniversary has occasioned a fresh round of anxious, if not exactly new, commentary about the rifts between Israeli and Diaspora Jewry. Some Diaspora complaints, especially with respect to religion and refugees, are valid and should be heeded by Jerusalem.

But to the extent that the Diaspora’s objections are prompted by the nonchalance of the supposedly nonvulnerable when it comes to Israel’s security choices, then the complaints are worse than feckless. They provide moral sustenance for Hamas in its efforts to win sympathy for its strategy of wanton aggression and reckless endangerment. And they foster the illusion that there’s some easy and morally stainless way by which Jews can exercise the responsibilities of political power.

Though not Jewish, Adam Armoush was once one of the nonchalant when it came to what it means to be Jewish in the 21st century. Presumably no longer. For Jews, it’s a painful, useful reminder that Israel is not their vanity. It’s their safeguard.