ORBETELLO, Italy — On Friday, the first day that Italians needed to present a nationwide health passport for access to indoor dining, museums, gyms, theaters and a wide range of social activities, Margherita Catenuto, 18, from Sicily, proudly showed a bar code at the Capitoline Museum in Rome certifying that she was vaccinated.

“It’s like showing you have a conscience,” said Ms. Catenuto as she walked in. “You do it for yourself, and you do it for others. It’s very sensible.”

Similar measures to stem the coronavirus pandemic have prompted large protests in France and bitterly split Americans between cities that will require vaccine passes, like New York, and entire parts of the country that consider even masks an affront to their rights. But Italians have mostly greeted their new Green Pass with widespread acceptance and, after some compromises, near political consensus.

After a long populist period that prized anti-establishment fervor and viral propaganda over pragmatism and expertise, Italians are suddenly enjoying a high season of rationality.

“For things to get better, get vaccinated and respect the rules,” Prime Minister Mario Draghi, the most unapologetically establishment prime minister in Europe, told reporters on Friday before Parliament’s summer recess.

On Friday, signs outside movie theaters reminded patrons to bring their Green Passes — proof of a vaccination, a negative test swab taken in recent days or proof of a past virus infection — which they can download or print out. Restaurant workers checked certificates along with temperatures and reservations. Tourists can provide proof of vaccination with a vaccine accepted by European Medicines Agency.

“Do you have a Green Pass,” a hostess at an Orbetello sushi restaurant asked Laura Novelli as she showed up for lunch with a friend. She didn’t, nor did she have a negative swab test result or proof that she had recovered from Covid. “I didn’t even think about it,” the 26-year-old waitress told the hostess who turned her away with a shrug.

The notion that Italy under Mr. Draghi is doing reasonable things to help bring Italy out of the pandemic and into recovery has translated into broad support for what is now Europe’s most expansive measure in countering the spread of the Delta variant.

A recent poll published in Italy’s largest newspaper, Corriere della Sera, showed that 66 percent of Italians support the Green Pass, and populist leaders who once cast doubt on vaccines have largely gotten with the program.

“Having a reasonable leader helps, but I think Italians were reasonable in this crisis from the very beginning,” said Ferruccio De Bortoli, a columnist and former editor of the newspaper. He added that “this goes against the myth of irrational Italians.”

On Thursday night, the government announced that starting in September, the pass will also be required for schoolteachers, school administrators and university students. Teachers who don’t get the pass won’t be allowed into school. After five absences, teachers will stop receiving salaries.

Mr. Draghi has called returning to in-school learning a “fundamental objective.”

In September the pass will also be required to board ferries and buses traveling between more than two regions and on planes and high-speed trains. People who enter restricted areas without the pass, and business owners who let them in, face a fine of up to 1,000 euros — more than $1,180. A business that violates the rule can be closed for one to 10 days.

That did not stop the hostess at the sushi restaurant, who said the pass was wreaking havoc on reservations and business on its first day, from offering to look the other way for two teenage boys who did not have certifications. They declined and stepped back onto the street.

“I like to travel and wherever you go you need this freaking pass,” said one of the teenagers, Giovanni Galatolo, 18. “I’m getting vaccinated on Tuesday.”

The government argues that the pass will increase economic activity, not least by allowing more of normal life to resume. For example, seating capacity on the national high-speed train network will be increased from 50 percent to 80 percent, meaning more business travel and economic activity.

But it is also clearly intended to push Italians like Mr. Galatolo to get vaccinated.

Mr. Draghi, whose government consists of a grand coalition of parties, has exhibited a flair for putting populist politicians who traffic in spreading unreasonable doubts in their place. That includes Matteo Salvini, the leader of the nationalist League party and once the most powerful politician in Italy, who has struggled for relevance under the plain-spoken Mr. Draghi.

Mr. Salvini has staked out an ambiguous, have-it-both-ways position on the vaccine. One day he dips back into the populism that once made him Italy’s most popular politician, saying that those opposed to vaccinations should be listened to, that vaccines are useless for young people, and that the Green Pass should not be required to enter restaurants and bars. The next he declares support for Mr. Draghi and his policies.

Last month, when he suggested that a broader Green Pass would deprive half of Italians “of their right to life,” Mr. Draghi would have none of it.

“The appeal to not getting vaccinated is an appeal to die,” Mr. Draghi said in response to Mr. Salvini’s remarks. “You don’t get a vaccine, you get sick, you die.” The refusal to get vaccinated, he added, would “make people die.”

The next morning, Mr. Salvini got vaccinated.

Mr. Salvini said he had already booked his vaccination, and that he did it not based on what Mr. Draghi said but as a “free choice and not because someone imposed it on me.”

But it’s now clear who is calling the shots, especially since the pro-business base of Mr. Salvini’s own party supports Mr. Draghi in the hopes of getting the economy moving again.

Mr. Draghi has “obviously robbed populism of its voice,” said Sergio Fabbrini, a professor of politics and international relations and dean of the Political Science Department at Luiss, a university in Rome.

The Green Pass is by no means a panacea to the pandemic, and there are still major hurdles for the government to overcome. Younger Italians have proved more resistant to getting vaccinated, but some Italian regions have mobilized inoculation campaigns at their beaches, nightclubs and bars. In Sicily officials offered vaccines in ice cream shops and pizzerias.

More troubling, especially given the awful toll of the virus on older Italians during the first waves of the pandemic, is that about 11 percent of Italians over the age of 60 are still not vaccinated.

Sporadic protests by anti-vaccination activists, who were encouraged during the anti-establishment political campaigns of Five Star and the League, have broken out.

While the government considers about 7 to 8 percent of Italians as strongly opposed to vaccines, it sees an equal percentage as reachable, but they just haven’t gotten around to it or don’t see the point. The Green Pass, they argue, has already prompted a spike in vaccination bookings, and the government is confident a broader use of the pass will prompt even more inoculations.

Ms. Novelli, who was turned away from the sushi restaurant for not having a Green Pass, said she wasn’t ideologically opposed to inoculation, but had hesitated for fear of missing work with side effects from a fever. She said she understood the rationale of the pass, and said if it became necessary to work, “I’ll have to do it,” but she said she wouldn’t get vaccinated just to eat in a sushi restaurant.

“I did,” said her friend Laura Cretu, who had recently been vaccinated and added that she also needed it to go to university classes in September. “Without the Green Pass,” she said, “you can’t do anything.”

Reporting was contributed by Emma Bubola in Rome, Gaia Pianigiani in Siena and Elisabetta Povoledo in Pallanza, Italy.