For more than a century, motorised vehicles have been banned from Mackinac Island in Michigan - giving the former Revolutionary War battle site a unique charm and turning it into a tourist haven.

The ban is so strictly enforced that when President Gerald Ford visited in 1975, he and first lady Betty Ford travelled by horse-drawn carriage.

But the Trump administration is known for its norm-breaking, and on Saturday, vice president Mike Pence rumbled across the island in an eight-vehicle motorcade.

Mr Pence was on the island to speak at the Michigan Republican Party's leadership conference, the first ever sitting vice president to address it in its 60-year history.

Ron Fournier, a Michigan native and former Washington bureau chief for the Associated Press, said the motorcade was "obscene”.

Mackinac Island: A motor-free tourist heaven Show all 12 1 /12 Mackinac Island: A motor-free tourist heaven Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan Tourists cycle on Market Street. No motorised vehicles are allowed on the island Getty Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan Downtown area of Mackinac Island Getty Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan The island has been motor-free since 1898 Getty Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan The Round Island Light, also known as the "Old Round Island Point Lighthouse is a lighthouse located on the west shore of Round Island in the shipping lanes of the Straits of Mackinac Getty/iStock Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan Downtown Mackinac Island Michael Deemer Getty/iStock Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan A harbour view from Lake Huron Getty/iStock Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan One of the cycle paths on the island Getty/iStock Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan The famous Grand Hotel Getty/iStock Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan Fog encroaches on the bridge from Mackinac Island Getty/iStock Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan Mackinaw City, Michigan, USA - August 8, 2018: Horse and carriage and bicycles line the streets of Mackinaw Island. The popular island has a ban on automobiles and and transportation is limited to foot, bike or horse. ehrlif Getty Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan Downtown Mackinac Island at sunset Michael Deemer Getty/iStock Mackinac Island: A motor-free tourist heaven Mackinac Island, Michigan A team of horses pulling a carriage in front of a victorian home high on West Bluff Road Getty/iStock

“Sacrilege,” he tweeted, adding that “no security expert would claim it's necessary”.

Another local posted: "Even President Gerald Ford rode in a horse drawn carriage. Is there no limit to the crass elitist raised middle finger to America?"

But others said it was a sign that times had changed, with presidents and their senior officials facing increased security threats.

There are typically only a few exemptions to the motorised vehicle ban - emergency vehicles and snowmobiles in winter are among those allowed.

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