You can’t impose patriotism. So what to do then when a candy brand with long-standing ties to a communist past demands a national pride campaign to combat creeping apathy among young consumers? Use reverse psychology by taking away something that was being taken for granted.

The American ROM campaign challenged the patriotism of Romanians by replacing the candy bar’s original wrapper–-which had been enveloped in the country’s flag since its origin in 1964 when it was the only choice in chocolate bar–-with an American flag. Drastic, perhaps, but the campaign resulted in a stunning display of national loyalty, huge increases in market share, and not one but two Grand Prix, for Promo & Activation as well as in the direct category, at Cannes this week.

“It was tough because the client demanded a national pride campaign but that was impossible to do in a context where younger generations are voting with their feet in Romania,” says Adrian Botan, the creative director for McCann Erickson Romania. “They see their future abroad and are kind of disappointed by their country. We had to create something to rebel against so people would discover their national pride.”

ROM had lost considerable market share to American imports such as Snickers, so this controversial move was a provocation and something of an outrage. Facebook groups popped up reviling ROM’s new face and debating the very notion of what it meant to be Romanian. Flash mobs gathered to protest, and the stunt made the national news.

Leaving aside where this leaves U.S.-Romanian relations, it all resulted in €300,000 in free media, according to the agency, and a 79% increase in market share which put the product on top of its category. The offending American ROM bars sold out as well. Normally a red flag, negative comments were even met with delight, says Botan. “The account director was calling me and saying, ‘Wow, excellent, we have thousands of negative comments. That’s exactly what we were looking for.'”