Italy’s deputy prime minister and interior minister, Matteo Salvini, is one step away from facing trial after a surprise court ruling determined that he be tried for kidnapping.

In August, prosecutors in Agrigento, Sicily, placed Salvini, who is leader of the far-right party the League, under investigation for the alleged kidnapping and detention of 177 migrants whom he prevented from disembarking the Italian coastguard ship Ubaldo Diciotti.

The ship had been docked for six days at the Sicilian port of Catania as Salvini maintained a standoff with the EU in an attempt to push other member states to take in the migrants. The Catholic church, Ireland and Albania, which is not an EU state, eventually agreed to host the mostly Eritrean migrants.

“I could face up to 15 years of jail because I have stopped the disembarking of illegals in Italy,” Salvini wrote on Facebook in response. “I’m speechless. Am I afraid? Not at all. I’m not going to give up on this. Now the decision will pass through the Senate. We’ll see how it goes …”

Since Salvini is a government minister, the accusations against him will be put to parliamentarians or senators, who will vote either for him to stand trial or for the proceedings to be halted.

Salvini said he was confident he had the support of the senators from the League. But the support of his coalition partners, the populist Five Star Movement, is far less assured. One of the M5S’s founding principles has always been to ask for the resignation of politicians under investigation.

Until last year, this principle was written in the Movement’s own statutes. The rule was part of the party’s attempt to present a clean image and distance itself from corruption.

Two years ago, Luigi Di Maio, the Italian deputy prime minister and leader of the M5S, called for the resignation of Angelino Alfano, minister of the interior at the time, who was under investigation for abuse of office.

Di Maio said: “We cannot allow a minister of interior under investigation to remain in office. Alfano must resign.”

Should the M5S vote against criminal proceedings, thereby rescuing Salvini from a possible conviction, the party would lose credibility among its supporters. But if it supported the investigation against Salvini, then it risks losing him and their political alliance, which would cause the entire government to fall.

The ruling by the court of ministers on Thursday came as a surprise, as the chief prosecutor of Catania, Carmelo Zuccaro, known for launching several investigations against rescue boats operated by aid groups, a few months ago dropped the charges against Salvini, suggesting the court of ministers would not put him on trial.

‘’If what I did means I’m a kidnapper,” Salvini said, “well, then you can consider me as a kidnapper for the coming months.’’