EVERY four years the United States holds an election that can change national policy and unseat many decision-makers. Every five years China holds a selection process that can do the same thing. Communist Party officials tout it as evidence of a well-ordered rhythm in their country’s politics. This year it may turn out as unpredictable as America’s election in 2016.

The people up for re-selection are the 350-odd members of the party’s Central Committee, the political elite, along with its decision-taking subsets: the Politburo, the Politburo’s Standing Committee (a sort of inner cabinet) and the army’s ruling council. The choice of new leaders will be made at a party congress—the 19th since the founding one in 1921—which is expected to be held in Beijing in October or November, and at a meeting of the newly selected Central Committee which will be held directly afterwards.

Party congresses, which are attended by more than 2,000 hand-picked delegates, and the Central Committee meetings that follow them, are little more than rubber-stamp affairs. But they are of huge symbolic importance to Chinese leaders. They matter for three reasons. First, they endorse a sweeping reshuffle of the leadership that is decided in advance during secretive horsetrading among the elite. The coming congress will be Mr Xi’s first opportunity to pack the Central Committee with his own allies; the outgoing one was picked in 2012, when he took over, not by him but by the people then running the country, including his two predecessors. After previous congresses held five years into a leader’s normally ten-year term—that is, those convened in 2007 and 1997—it became clear who that leader’s successor was likely to be. If the coming meetings are like those earlier ones—a big if—they will give a strong clue to Mr Xi’s choice of successor and start the transition from one generation of leaders to another.

Second, congresses can amend the party’s constitution. China’s leaders like the document to give credit to their favourite ideological themes (and Mr Xi is particularly keen on ideology). When Jiang Zemin stepped down as party chief in 2002 his buzzwords were duly incorporated; so too were those of his successor, Hu Jintao, five years later. Mr Xi’s contribution to party-thought—such as on the need to purge it of corruption while strengthening its grip—is likely to gain similar recognition.

Third, congresses are the setting for a kind of state-of-the-union speech by the party leader, reflecting an elite consensus hammered out during the circulation of numerous drafts. In the coming months, Mr Xi will be devoting most of his political energy to ensuring that his will prevails in all three of these aspects. His authority in the coming years will hugely depend on the degree to which he succeeds.

Preparations for the gatherings are under way. They involve a massive operation for the selection of congress delegates. On paper, this is a bottom-up exercise. Party committees down to village level are choosing people who will then choose other representatives who, by mid-summer, will make the final pick. Thousands of party members are also scrutinising the party’s charter, looking for bits that might need changing.

It may sound like a vast exercise in democratic consultation, but Mr Xi is leaving little to chance. Provincial party bosses are required to make sure that all goes to (his) plan. Over the past year, Mr Xi has appointed several new provincial leaders, all allies, who will doubtless comply.

Hands up who likes Xi

Those chosen to attend the congress will follow orders, too, especially when it comes to casting their votes for members of the new Central Committee. And the newly selected committee will stick even closer to script. The processes that lead to its selection of the party’s and army’s most senior leaders are obscure—a bit like the picking of cardinals in the Vatican. But an account in the official media of what happened in 2007 suggests that at some point in the summer, Mr Xi will convene a secret meeting of the current Central Committee and other grandees for a straw poll to rank about 200 potential members of the new Politburo (which now has 25 members). This is called “democratic recommendation”, although those taking part will be mindful of who Mr Xi’s favourites are.

Candidates for the Politburo must fulfil certain criteria, such as holding ministerial rank. For the coming reshuffle, Mr Xi has added a new stipulation: faithful implementation of his policies. For all his power, Mr Xi has struggled with widespread passive resistance to his economic reforms. To ram home the importance of obedience, Mr Xi recently held what he called a “democratic life session” at which Politburo members read out Mao-era-style self-criticisms as well as professions of loyalty to Mr Xi as the “core” leader (as the party decided last October to call him).

By August, when Mr Xi and his colleagues hold an annual retreat at a beach resort near Beijing, the initial lists of leaders will be ready. Probably in October, the Central Committee will hold its last meeting before the congress to approve its documents. The “19th Big” will start soon after, and will last for about a week. The first meeting of the new Central Committee will take place the next day, followed immediately by the unveiling before the press of Mr Xi’s new lineup (no questions allowed, if officials stick to precedent).

The process is cumbersome and elaborate, but over the past 20 years it has produced remarkably stable transfers of power for a party previously prone to turbulent ones. This has been helped by the introduction of unwritten rules: a limit of two terms for the post of general secretary, and compulsory retirement for Politburo members if they are 68 or over at the time of a congress. Mr Xi, however, is widely believed to be impatient with these restrictions. He has ignored the party’s hallowed notion of “collective leadership”, by accruing more power to himself than his post-Mao predecessors did.

If precedent is adhered to, five of the seven members of the Politburo’s Standing Committee, six of its other members and four of the 11 members of the party’s Central Military Commission (as the army council is known) will all start drawing their pensions. In addition, roughly half the 200-odd full members of the Central Committee (its other members, known as alternates, do not have voting rights) will retire, or will have been arrested during Mr Xi’s anti-corruption campaign. This would make the political turnover at this year’s gatherings the biggest for decades, akin to changing half the members of the House of Representatives and three-quarters of the cabinet.

Until late in 2016 there was little to suggest any deviation from the informal rules. But in October Deng Maosheng, a director of the party’s Central Policy Research Office, dropped a bombshell by calling the party’s system of retirement ages “folklore”—a custom, not a regulation.

The deliberate raising of doubts about retirement ages has triggered a round of rumour and concern in Beijing that Mr Xi may be considering going further. The main focus is his own role. Mr Xi is in the middle of his assumed-to-be ten-year term. By institutional tradition, any party leader must have served at least five years in the Standing Committee before getting the top job. So if Mr Xi is to abide by the ten-year rule, his successor will be someone who joins the Standing Committee right after the coming congress.

But there is widespread speculation that Mr Xi might seek to stay on in some capacity when his term ends in 2022. He might, for instance, retire as state president (for which post there is a clear two-term limit) but continue as party general-secretary. He faces a trade-off. The more he breaks with precedent, the longer he will retain power—but the more personalised and therefore more unstable the political system itself may become. Trying to square that circle will be Mr Xi’s biggest challenge in the politicking of the year ahead.