Tourists watched from an overpass across Las Vegas Boulevard as police led workers wearing red union shirts one-by-one into a white police bus.
Police arrested 98 protesters, according to Metro Police Capt. Todd Fasulo. The workers chanted, "If we don't get no contract, you don't get no peace," as they waited to be taken away.
Las Vegas' largest and most powerful union has been in contract talks with Cosmopolitan Las Vegas owner Deutsche Bank for two years.
Earlier this year, the 54,000-member union held two one-day pickets outside the casino, which sits on a bustling corner in the heart of the tourist corridor. They marked Culinary Workers Local 226's first pickets on the Strip since 2003.
Wednesday's action was the first time union members deployed civil disobedience, the tactical use of nonviolent law breaking, outside a unionized casino in more than two decades, according to union spokeswoman Yvanna Cancela.
Cosmopolitan spokeswoman Amy Rossetti said management is continuing to negotiate with labor to "find a fair agreement." She added that the union was negotiating with casino management, not with Deutsche Bank directly.
Protesters shut down rush hour traffic for more than an hour in both directions on the block that is also home to the Bellagio, Aria and Planet Hollywood casinos. Cancela estimated the crowd at about 1,500 people.
Moments before her hands were bound with a zip-tie, Janet Hill said she decided to get arrested to send management a message.
"They need to give workers here a contract; it affects us all," said Hill, a porter at the Flamingo casino down the Strip.
Contract negotiations will open for most other Strip casinos in April.
Talks with the Cosmopolitan have stalled on a range of issues, including wages, health care and job security, Cancela said.
The 2-year-old Cosmopolitan was built by the German investment bank after its original developer defaulted. It is one of just a handful of non-unionized casinos on the Strip, along with the Venetian, the Hard Rock Hotel and Casino, and the Palms.
Culinary Union members receive free health care and are paid above-average wages. Housekeepers in most Strip hotels start at $16 an hour and receive a pension.
A majority of Cosmopolitan service workers signed cards in 2010 saying they wanted representation.
On Wednesday, protesters said they were worried that Deutsche Bank was stalling because it intends to sell the casino and doesn't want to be burdened by a union contract.
Most tourists walked by the demonstration without breaking their stride. One couple turned around in surprise when a protester booed them for crossing the picket line.
Several visitors said they were annoyed at the inconvenience. But a few cheered on the workers as they marched in their navy, emerald and black casino uniforms. A few even joined in.
James Lewis, of Australia, took a photo of himself holding a sign reading, "No Justice, No Peace."
"I was surprised because I didn't know this was an issue here," said Lewis, who was in town for a friend's 40th birthday party. "I come from a place where health care is free, so this is something completely foreign."
Paulina Corona came to the protest in the brown uniform she wears as a housekeeper at the Mirage hotel-casino. She said the demonstration was important because mutual support creates strength.
"This is a union, and everybody is in it together. When there are problems at the Mirage, everyone goes there," she said.
Corona, 58, said that as a cancer survivor she worries that management could make workers shoulder more of their health care costs.
"Every day, they try to ask for more things," she said.
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