MILAN (AP) — Voters in the wealthy northern Italian regions of Lombardy and Veneto decided Sunday if they want to seek greater autonomy from Rome, riding a global tide of self-determination that has swamped Spain's Catalonia region.

While the twin referendums are non-binding, a resounding "yes" vote would give the presidents of the neighboring regions more leverage in negotiations to seek a greater share of tax revenue and to grab more responsibility from Italy's central government.

The leaders want more powers in areas such as security, immigration, education and the environment.

Unlike in Catalonia, the referendums do not seek independence and have been approved by Italy's constitutional court. Still, the autonomy drive is a powerful threat to Rome's authority. Together, Veneto and Lombardy account for 30 percent of Italy's GDP and nearly one-quarter of the nation's electorate.

At their respective polling places, Lombardy President Roberto Maroni and Veneto President Luca Zaia cast the referendum as a historic opportunity.

"A page of history is being written," Zaia said as he voted in Treviso province, north of Venice. "Veneto will not be the same as before."

Maroni, speaking as he voted in Varese province north of Milan, said the referendum represented "a historic occasion" for the two leaders to seek "greater responsibilities and resources."

After 12 hours of voting, the turnout in Veneto was high enough to make valid the pending results of its ballot initiative seeking popular backing to grab power from Rome valid.

In Veneto, 52 percent of the region's 4 million voters cast ballots. No quorum was set in Lombardy, where turnout was lower, above 30 percent of the 8 million voters.

Still, that was likely to satisfy Maroni, who said he was looking for final turnout above the 34 percent who voted in a 2001 constitutional referendum.

Both regions are run by the anti-migrant, anti-Europe Northern League, which has long given up its founding goal of secession as it seeks a national profile.

Northern League leader Matteo Salvini said he intends to push for autonomy no matter the final turnout, as long as the yes vote wins.

"No matter what, if some millions of people give us the mandate, we will go negotiate tomorrow with the central government," Salvini said.

Critically, some of the key areas where the two northern regions want more autonomy — including greater fiscal control, immigration and security issues — are beyond the scope defined by the constitution, thereby requiring difficult-to-achieve constitutional changes.

"I don't think this is possible," said Paolo Natale, a political scientist at Milan's state university. "It will be difficult for the state to accept that they take over education and security policy. The management of immigration policy has to be done at a national level."

Other policy areas where autonomy is easier to win — including environmental and cultural protection — have not been on the front lines of the referendum campaign.

With the Democratic Party urging its voters to abstain, the votes Sunday will measure the mood ahead of a national election next year, when Berlusconi says he will make autonomy for all of Italy's regions part of the center-right agenda.

Critics argue the non-binding votes carry no legal weight, are not needed to trigger autonomy negotiations and are a costly waste of resources.

Yet such arguments play into the hands of the "yes" campaigners, who see such put-downs as part of the anti-democratic, centrist decision-making in Rome. Those sentiments have been echoed in the Catalan independence drive in Spain, in the U.S. election of Donald Trump as president and in Britain's vote to leave the 28-nation European Union.

The Italian constitution already grants varying levels of autonomy to five regions in recognition of their special status: the largely German-speaking Trentino-Alto Adige; the French-speaking Aosta; the islands of Sardinia and Sicily; and the region of Friuli-Venezia Giulia for its position on the border with then-Yugoslavia as a Cold War hedge.

Veneto was twice denied by the constitutional court requests for referendums for fiscal autonomy before a 2001 constitutional change defined the policy areas for which Italy's 15 ordinary regions can seek autonomy.

The ballots Sunday are the first to pose the question to voters. Emilia Romagna, a center-left region, has recently opened talks with Rome on greater autonomy without holding a popular vote.