Leading article: Israel's tricky electoral arithmetic

There is good news and bad news from the Israeli elections. The good news is that, despite leading in the opinion polls for several weeks, the right-wing Likud party, led by Benjamin Netanyahu, was pipped at the post by thecentrist Kadima party, led by the former foreign minister, Tzipi Livni. There is, as Ms Livni said when she claimed victory, still a moderate centre in Israeli politics. There is still a quorum that favours continuing the peace process. It is true that Kadima emerged as the largest party by the narrowest of margins – just one Knesset seat – but it defied early forecasts of defeat.

The rest of the news, alas, is less good. One reason why Likud may have been deprived of its expected victory was the strong performance of Avigdor Lieberman's ultra-nationalist party, Yisrael Beiteinu.

Between them, these two parties comecloser to having the necessary 61 seats to form a government than Kadima and Ehud Barak's Labour. This arithmetic means that President Shimon Peres might be inclined to give Mr Netanyahu first crack at forming a coalition. Were he to succeed, though, the resulting government could turn out to be less flexible in relation to the peace process than one in which Mr Netanyahu had more room for manoeuvre.

The increased support for Mr Lieberman's party – 15 seats compared with 11 last time around – also shows beyond doubt that a sizeable minority of Israelis is averse to the peace process either as it was, or as they believe it might develop, now that Barack Obama is US President. Mr Lieberman's likely position as "king-maker" threatens to make all Israeli politics hostage to a minority group far to the right of centre.

In this respect, the result represents the worst of several possible worlds. Not only has the nationalist right emerged stronger, but the whole point of holding this election – to break the stalemate Ms Livni encountered when she tried to form a government late last year – has been negated. If the vote has shown anything, it is that Israel's electoral system as it stands works against stable government. Whoever forms the country's next government should consider addressing this as a priority.