As Romeo and Juliet proved, there can be love and wedding plans, and even a friar eager to bring the two sides together, but still no wedding.The same holds true far from Verona, here in Jerusalem.Prime Minister Benjamin Netanyahu had every reason to seek a national-unity government with Zionist Union leader Isaac Herzog.He had a crumbling, undependable coalition of 61 MKs in which every backbencher was king. He was vexed by Likud legislators with delusions of grandeur.He had months of diplomatic challenges ahead, dealing with a president of the United States who could cause Israel problems in his final 284 days in office.And, he had the simple fact that he never believed in having a right-wing coalition in the first place, only forming the overly homogeneous government he did because he had to shift to the right during his campaign and it was hard walking back.Herzog also had plenty of reasons to enter a national- unity government with Netanyahu. He had polls that were predicting his party’s political demise under his leadership.He had the history of Labor Party leaders who did not last long with none winning a second term in decades. And he had his genuine desire to serve the country in the vacant Foreign Affairs portfolio, where he could use his skills to improve Israel’s future.There were countless mediators.Former Prime Minister’s Office director-general Yossi Kucik’s name was revealed over the weekend, but there were many others. Some acted on Netanyahu’s behalf.Some on Herzog’s. But most were just well-meaning people who wanted the bride and groom to come together.Unlike with Romeo and Julio, however, it is not death that will keep Netanyahu and Herzog apart.The probe into alleged campaign fund-raising violations Herzog is facing will prevent a unity government from being formed. But it is not the only reason.There is also simple math. Netanyahu and Herzog would face rebels in their parties who would not accept the deal. Bayit Yehudi would be forced out. The end result would be an upgrade from 61 MKs to not much more.And there is also fate.Star-crossed lovers can have the best of intentions, but still remain forever apart.