ROME - The Italian Senate will return Tuesday from its summer vacation to set a crucial date for a no-confidence vote on Prime Minister Giuseppe Conte's populist government.

That development followed a meeting Monday of party whips in the Senate who failed to unanimously agree on the date of the no-confidence vote.

Interior Minister Matteo Salvini declared last week that his right-wing League party no longer supports Conte and is pressing for a no-confidence vote in the next few days. He's calculating that Conte will lose and resign, triggering what Salvini hopes will be a new election as early as this fall.

Eager to become premier himself, Salvini wants to go to the polls as soon as possible to capitalize both on the League's rising popularity and the waning support for his senior coalition partner, the populist 5-Star Movement.

Italy's main opposition party, the center-left Democratic Party (PD), is already divided over its future strategy. Party secretary Nicola Zingaretti issued a call for unity Monday, reiterating that the key decision on whether and when to call an early election is in the hands of President Sergio Mattarella. He added that the Democrats are not afraid of facing an early ballot.

But former premier Matteo Renzi, who still has a strong influence among the Democrats' senators, suggested Sunday the party should seek a possible alliance with the 5-Stars and other moderate forces to stop Salvini and derail his plan for a new election in October.

Sales tax, migrant issues

Italy has to draft a painful budget law by the end of October and have it approved by parliament by the end of the year. The government in place will have to find about 23 billion euro ($25.8 billion) in financial resources to avoid a planned sales tax hike, which would prove highly unpopular with voters and weigh on the electoral campaign.

Depending on the outcome of the no-confidence votes in the Senate and the House, the president could still try to guide the creation of a transition government, headed by Conte or someone else, to handle the budget law and lead Italy to a new election that could be as late as next year.

Still, it's not clear that such a government would win the needed majority in parliament.

Salvini's strong anti-migrant stance is credited with the League's surge in popularity. After claiming just 17% of the vote in Italy's 2018 national election, the League won 34% in European elections this spring.

The 5-Stars, meanwhile, have seen their support shrink from nearly 33% in the 2018 election to 17% in the European elections in May.