Donald Trump has dealt with labor unions throughout his long and lucrative career in real estate. Though it's nothing most candidates would brag about in a Republican presidential primary, the GOP front-runner likes to say that he and organized labor get along just swell.

“I have great relationships with unions,” Trump told Newsweek last year.

A few hundred mostly immigrant hotel workers in Las Vegas might disagree.

For the last half-year, Trump has locked horns with a powerful Nevada union over the Trump International Hotel in Las Vegas. Culinary Union Local 226 won a union election at the posh 64-story hotel in December. But since then, Trump's team has been challenging the results of the election, accusing the union of coercing workers and improperly influencing the outcome.

In typical Trumpian fashion, the fight has been a litigious one, full of accusations and counter-accusations. And for now, Trump is losing.

Trump's team claimed that union staffers, organizing committee leaders and even federal officials tried to sway the election in the union's favor. But last week, a hearing officer with the National Labor Relations Board found no merit in those claims. She recommended that the objections of hotel management "be overruled in their entirety," and that the election results be made official.

The hotel has the option to appeal that decision, or simply begin bargaining with the workers on their first contract. Bethany Khan, a spokeswoman for the union, said it's time that Trump and his partners took the latter path.

"He says he's a great negotiator and businessman. Then he shouldn't be afraid of some housekeepers," Khan said.

A Trump spokeswoman didn't respond to emailed questions about the labor dispute.

The friction at the hotel stretches back to at least August, when a union organizing campaign apparently was in full swing. There are at least two batches of so-called unfair labor practices complaints pending against the hotel, including workers being threatened, punished and even fired for supporting the union, according to NLRB filings. 

In October, the hotel's owners filed a lawsuit against the union, accusing it of false advertising. The union had distributed flyers saying that Trump had stayed at a union hotel in Las Vegas during a visit rather than at the Trump International. "If Trump chooses to stay in a union hotel, why can't Trump Hotel workers choose to form a union?" the flyers asked. The Trump International owners said the union's claim was false and was made "to damage the reputation of the hotel." 

Local 226, an affiliate of the hotel workers' union Unite Here, represents many of the housekeepers, restaurant workers and casino workers on the Vegas strip. When it comes to casinos and hotels, Vegas is pretty much a union town these days, well known for having solid wages for service workers. Local 226 says Trump's property is one of just a few on the strip where housekeepers are not currently unionized. The union claims that the housekeepers at the Trump International -- many of whom are Latino and Filipino, according to NLRB filings -- earn $3.30 less per hour than the average union housekeepers on the strip.

Despite Trump's claims of collaboration with unions, the Trump International appears intent on keeping the culinary union out of the hotel. According to filings with the Labor Department, in 2014, Trump Ruffin Commercial, the corporation affiliated with the hotel, retained the services of the Labor Relations Institute, a firm known for so-called union avoidance work. According to its contract with the hotel, the company was providing an expert to "educate and prepare your employees for union organizing."

That included what were deemed "inoculation meetings," in which a consultant would "communicate your message directly to employees." Local 226 claims the hotel also brought in consultants from Cruz & Associates, another firm known for helping keep unions out of the workplace.

Yet the union still managed to eke out a victory in the December election. According to the NLRB, 238 workers voted in favor of union representation, compared with 209 against. That breaks down to roughly 53 percent voting yes, and 47 percent voting no.

"Donald Trump would love to win a presidential election by that margin," Khan said.