The defeat was devastating. Jerusalem was leveled, nearly a thousand villages were demolished, and more than a half a million Jews were killed, according to Roman historian Cassius Dio. Countless others, including many rabbis, were sold into slavery. It was the beginning of the great Diaspora, in which Jews would be scattered throughout Europe and elsewhere--defenseless, marginalized, and persecuted. The world would not see a Jewish army again for nearly two thousand years, when the modern state of Israel was founded.
In a "what if" speculation I've wondered how history would have played out had Bar Kokhba and Rabbi Akiva quelled the insurgency and negotiated with the Romans rather than rebelling against them. The Emperor Hadrian was not totally hostile to Judaism. He permitted Jews to return to Jerusalem (they were expelled after the war of 70 CE), and even allowed, but then reneged on, the rebuilding of the temple in Jerusalem.
If Bar Kokhba's second-century Jewish army was powerful enough to stand up to the Roman army at the height of its power, how much more powerful would it have been a few hundred years later when the Roman Empire collapsed? The fragmented kingdoms that emerged in Europe were constantly at war with each other with relatively small armies. Even hundreds of years later the crusading armies were minuscule compared to Bar Kokhba's second-century army. A mighty Jewish army, larger and stronger than Bar Kokhba's, would surely have been formidable if not unbeatable. If that were the case, it's possible that Judaism would have become the dominant world religion.
It's an intriguing idea, but the reality is that "Messiah" Bar Kokhba's "heroism" was ultimately suicidal and incredibly destructive to Jews and Judaism.
Given the history of Jewish "Messiahs," who today are considered false but still are not rejected as Jews--indeed, some are still honored and revered--how can Jews' shunning of Jesus be justified? In the spirit of reconciliation isn't it time for Jews to drop the Jesus phobia?