The current election season is full of surprises, but no one expected a major bombshell when Yisrael Beytenu called a press conference on Tuesday night to announce the party’s list for the next Knesset.

Two troublemakers — Tourism Minister Stas Misezhnikov and MK Anastassia Michaeli — had already been purged, and everybody anticipated it would be smooth sailing till the January 22 elections. So for the foreign minister and party leader Avigdor Liberman to fire his deputy, Danny Ayalon? No one saw that coming, and a day later, voters, party members, the media and even Ayalon’s closest aides still have no clue as to what lies behind the decision.

According to the deputy foreign minister’s spokesperson, Ofri Eliyahu, Ayalon himself was shocked over his dismissal two days before the deadline for parties to submit their election slates. Ayalon was reportedly in his car on his way to a party event in Jerusalem Tuesday evening when Liberman called and informed him that his presence would not be required for the next Knesset.

There are several theories as to why Liberman sacked his deputy so abruptly, but no definitive explanation. Yet.

Initially, observers surmised that Ayalon, 56, was booted from the party’s list for the same reasons Misezhnikov and Michaeli had to bow out — one or more missteps that ostensibly embarrassed the party. The former, a rather successful tourism minister, was accused earlier this year of regularly indulging in alcohol to excess, visiting strip clubs and leading a hard-partying, after-hours lifestyle. The latter was mainly known for clashing publicly with fellow MKs — as when she dumped a glass of water on Labor’s Raleb Majadele — and for making homophobic statements.

Ayalon, who was seventh on Yisrael Beytenu’s list for the 2009 elections, memorably embarrassed the Turkish ambassador when, in early 2010, the deputy minister invited Ankara’s envoy in Tel Aviv, Ahmed Oguz Celikkol, to the Foreign Ministry in Jerusalem. Celikkol was summoned to protest his country’s harsh criticism of Israeli policies vis-à-vis the Palestinians.

Before the meeting, Ayalon said he wouldn’t shake Celikkol’s hand, and once the envoy arrived, Ayalon made sure the Turk was seated humiliatingly below his Israeli hosts — on a low sofa — and had to look up at them. Furthermore, Ayalon told television crews in Hebrew to take note of the fact that the Israeli officials were not smiling and that no Turkish flag was placed on the table.

The episode caused a stir, and Ayalon was forced to apologize. It could be argued that Ayalon’s handling of the incident contributed significantly to the current frostiness of Jerusalem’s relations with Ankara. But was that the reason that Liberman, himself not known for excessive fondness for Turkey’s current government — or excessive diplomacy in his interactions, for that matter — gave Ayalon the boot three years later? Seems unlikely.

Some observers speculate that Liberman didn’t like the fact that Ayalon — a former Israeli ambassador to Washington – was outgoing and often interacted effectively with the media, and feared leaks to the press. According to one party official, Liberman had “lost trust” in his deputy.

But Liberman and Ayalon worked together pretty closely for four years, and it was often apparent to observers that the foreign minister approved of his deputy’s initiatives. Liberman doesn’t much like the press, and he seemed more than happy for Ayalon to be the one to present his policies to the outside world.

Lately, Ayalon’s work focused a lot on the issue of Jewish refugees from Arab countries who made their homes in Israel. He tried to elevate this issue to high on the international agenda, hoping to offset world attention on the Palestinian demand for a “right of return” to Israel for their refugees and descendants. Yet Liberman supported the project, and the party proudly lists it as one of its accomplishments in the Knesset term.

Another possibility is that Liberman axed Ayalon at the behest of prime minister and Likud party chairman Benjamin Netanyahu. Faced with heavy criticism about a Likud list that tilts too much to the right — and unable to make changes to the democratically selected Likud part of the joint Likud-Yisrael Beytenu Knesset slate — Netanyahu might have asked Liberman to purge his party’s contribution to the list of some of its more right-wing elements.

Anastassia Michaeli certainly fit that category. And more than the local minor embarrassment Michaeli, Ayalon was known internationally as a nationalist firebrand. Thus, gruffly showing Ayalon the door could convey the message that Likud-Yisrael Beytenu is distancing itself — to the extent that it can — from some of its more notorious hawks. But even this explanation is hard to accept, since Yisrael Beytenu is a hawkish party, its leader regularly calls Mahmoud Abbas “a political terrorist,” Ayalon did not steer a notably more radical course, and ditching him does very little to offset the radical impression underlined by the high placement of hawks like Danny Danon, Miri Regev and Moshe Feiglin on the Likud roster.

It’s true, too that while Ayalon is popular, especially among English-speaking Israelis, he is not one of Yisrael Beytenu’s superstars. Newcomer Yair Shamir, the son of former prime minister Yitzhak Shamir, veteran MK and Energy and Water Minister Uzi Landau, and Immigration Minister Sofa Landver are more highly regarded among party members. Still, that hardly amounts to grounds for dismissal.

In Haaretz on Wednesday, political analyst Yossi Verter gave three possible reasons for Ayalon’s surprise ouster. It could be Liberman’s belated response to the Turkish ambassador business — “It seems Liberman neither forgets nor forgives,” Verter mused. Alternatively, Verter speculates, Liberman hopes to become defense minister in the next government and therefore no longer needs a diplomat like Ayalon hanging around. Or, finally, it was a “preemptive step by Liberman concerning an issue involving Ayalon that has yet to be revealed.”

We’ve already ruled out the first of these as particularly unlikely. And militating against the second possibility is both the fact that Liberman has credibly expressed a preference to stay on as foreign minister, and the brusqueness with which Ayalon was told that he needs to find himself a new job. So of Verter’s trio, we’re left with the final possibility — the “issue… that has yet to be revealed.” Very intriguing.

Fact is, Ayalon didn’t even merit a gracious political obituary from his boss of the kind awarded the highly problematic Misezhnikov. Liberman expressed “great regret” at Misezhnikov’s ostensible decision to quit politics, saying that he “was supposed to be placed at a very high spot on the Knesset list and play a senior role in the future government.”

For now, Liberman is staying resolutely silent, and Ayalon resolutely diplomatic. Before heading to the airport on Wednesday to accompany Netanyahu on a difficult trip to Berlin — Liberman was originally scheduled to go too, but canceled at the last minute to “take care of party business” — Ayalon wished Yisrael Beytenu the best of luck in the elections, and had not a single bitter word for Liberman. “I certainly respect him,” Ayalon said. “The world of politics has its own rules.”