Though Benjamin Netanyahu’s opponents were quick to dub his latest political move a cynical ploy, the Israeli prime minister’s surprise formation of a unity government with Kadima, just days after announcing that early elections would be called in September, was neither cynical nor a ploy. Without Kadima, he truly had no choice but to call new elections. With Kadima, new elections are a costly waste of time.

Netanyahu faced two critical issues his government couldn’t resolve in its existing composition. One was the need to pass new legislation on drafting ultra-Orthodox yeshiva students by August 1, when the Supreme Court’s invalidation of a law exempting them from service takes effect. There is no solution to this problem that would be acceptable to both of Netanyahu’s main coalition partners: Yisrael Beiteinu wouldn’t accept anything that continues the exemptions, while the ultra-Orthodox Shas party wouldn’t accept anything that doesn’t. Yet if either of them quit, Netanyahu would lose his parliamentary majority.

The other issue, as economic analyst Nehemia Shtrasler noted, is the 2013 budget, which must be passed by December 31. Though Israel is still doing well by Western standards, its export-driven economy has inevitably been hurt by the global crisis, and particularly the downturn in Europe, its largest export market. It therefore faces a larger-than-expected deficit that necessitates budget cuts.

But when elections seem imminent – as they did, due to the crisis over the draft issue – it’s impossible to get Knesset members to agree to cuts; in fact, it’s usually impossible even to keep them from legislating hefty new expenditures. Hence, the only solution was new elections: A new government, with years yet to serve, could afford to make the necessary cuts.

With Kadima on board, however, both these issues become solvable. Netanyahu now has a solid majority even without Shas, enabling him to tackle the draft exemptions issue. And the government is now stable enough to survive the remaining 18 months of its term, so passing a responsible budget becomes feasible.

The unity government is clearly a better option than new elections, which not only cost a lot of money, but would largely put the government on hold during a potentially critical period: The Knesset would be dissolved, and MKs and ministers would be devoting most of their time and energy to campaigning. It’s possible that Netanyahu was hoping for this outcome all along.

Yet it was only the credible threat of new elections that persuaded Kadima to join him: With polls showing it would lose almost two-thirds of its Knesset seats if elections were held today, the party desperately needed more time to rehabilitate itself. New party chairman Shaul Mofaz had hoped to do so as leader of the opposition. But by announcing new elections, Netanyahu essentially gave him an ultimatum: If you want more time, you’ll have to join my government.

That may have been smart politics, but it was no cynical ploy: Had Mofaz not blinked, new elections would indeed have been held in September. And they would have been necessary.