Prime Minister Mario Draghi's government is on the brink of collapse after the 5-Star Movement said it will not take part in a parliamentary confidence vote on a cost-of-living aid package on Thursday.
Here are possible scenarios after the Senate vote, which could unleash political chaos in the country.
SAME PREMIER, SAME PARTNERS
President Sergio Mattarella could ask Draghi to call a fresh confidence vote in parliament next week. If the 5-Star decides to return to government ranks, the national unity coalition would remain in place, albeit battered and bruised.
Former premier and 5-Star leader Giuseppe Conte has left the door open for discussions with Draghi. However, 5-Star support is in steady decline and many party members are pushing for a complete cut with the government hoping to revive the party's flailing fortunes from opposition benches.
SAME PREMIER, FEWER PARTNERS
Draghi calls a confidence vote and musters the support of the rest of the coalition parties, including the rightist League, the centre-left Democratic Party (PD) and a sizeable group of former 5-Star politicians who split with Conte last month. The former European Central Bank chief would have a smaller, but nonetheless viable majority in both houses of parliament.
However, Draghi has said he would not stay in power without the 5-Star, and both the PD and the League have signalled they will not back another government if the 5-Star boycotts the Senate vote on Thursday.
Even if Draghi and the two parties change their mind, the operation would upset the government's internal equilibrium, since the coalition would be heavily skewed to the right, and demands from the remaining groups could trigger fresh turmoil.
EARLY ELECTIONS
If Draghi resigns and refuses to head a new administration, the president could dissolve parliament and call early elections that would take place in late September or October. Draghi might stay on as a caretaker, or Mattarella could ask someone else to take charge for the remaining weeks of the legislature.
However, Italy has not held an election in autumn since World War Two, with the final months of the year traditionally dedicated to drawing up the budget.
An early vote carries other risks. Italy still needs to meet many bureaucratic and legislative deadlines this year to secure billions of euros in European funds and these might be missed without a fully functioning government in place.
NEW PREMIER
In an effort to avoid early elections and financial turmoil, Mattarella could try to put together another unity administration calling in an institutional figure to lead a new coalition until elections, which are due in the first half of 2023.
However, it is hard to imagine the various components of Draghi's government rallying around a new figure.
(Reporting by Angelo Amante; Editing by Crispian Balmer, Raissa Kasolowsky and Alison Williams)