We wish them well. But we should sound a double warning — one about capability and one about the gap between campaign promises and office. About capability: if Obama’s and Livni’s leadership skills are comparable to their congeniality, then it’s all for the best. But if they turn out to be incompetent or incapable, America will be at its weakest and Israel at its worst. About the gap between campaign and office: no matter how much closer Obama and Livni are to European ideals, Obama would still be an American, not a European, president and Livni would still be an Israeli leader, not a Brussels bureaucrat. They lead countries with permanent interests which are sometimes at odds with Europe’s. At the moment of truth and in the hour of need, their popularity with the European commentariat may go south as fast as the financial markets have done.

These leaders may have to face major crises soon in their tenure. Livni may have to decide whether to launch a pre-emptive strike on Iran — a risky action fraught with dangers even if it turns out to be a success — or live with Iran’s bomb. If so, will she abandon Israel’s long-established doctrine of nuclear ambiguity? What if Iran chooses to heat up the Lebanese front again? Will she rise to the occasion? She might — and Europeans will be disappointed to see cute turn to ugly, as naked power is called in to save the day.

The same applies to Obama. Russia could do to Ukraine what it did to Georgia — or it could simply ensure that it’s a cold winter in Warsaw and Vilnius. Pakistan may collapse. Iran may test a nuclear device. What will he do? I suspect that he will not significantly stray from precedent — and that means he may disappoint Euro-enthusiasts who think Americans have elected a post-Kantian social democrat. It will not be so.