The acquittal of four Teamsters facing federal extortion charges for intimidating the cast and crew of “Top Chef’’ could have a profound effect on the labor movement, cementing legal protections for combative behavior on picket lines and possibly even emboldening more unions to use strong-arm tactics, some observers say.

But the negative publicity over ugly threats and aggressions allegedly committed by union members could also end up hurting organized labor, and the Teamsters in particular, despite the verdict, as unions continue their struggle to remain relevant.

Labor officials and supporters praised the outcome, saying it preserves protections for working-class people to demand better jobs.

“It’s a very, very important victory for working people,’’ said Steven A. Tolman, president of the Massachusetts AFL-CIO labor coalition, which filed a friend-of-the-court brief in the case. “How could I ever have had a union member join me on the picket line if this case was upheld? That’s what was at stake for us.’’

The four members of Charlestown-based Teamsters Local 25, who faced up to 20 years in prison, were each acquitted of conspiracy to extort and attempted extortion. According to prosecutors and witness testimony, the defendants bumped crew members, yelled profanities, lobbed racist and homophobic slurs, and slashed tires during production at the Milton restaurant Steel & Rye in 2014.

One of the defendants reached into a minivan containing “Top Chef’’ celebrity host Padma Lakshmi and said, “I’ll smash your pretty little face,’’ according to court documents.

Mark Mix, president of the National Right to Work Committee, a Springfield, Va.-based coalition working to reduce union influence, said the acquittal could lead to more aggressive union tactics.

“This case looks like it’s going to lead to a dramatic expansion of union officials’ ability to intimidate, to assault, and to increase their coercive power over workers and small businesses across the country,’’ he said. “Telling someone you’re going to smash their pretty little face is not legitimate union activity. Maybe in Boston. . . . But most people would say that’s not legitimate.’’

The acquittal, Mix added, will be used by “attorneys defending union thugs across America.’’

But the Teamsters’ victory does not mean their reputation hasn’t been hurt.

Gary Chaison, professor emeritus of labor relations at Clark University in Worcester, noted that the Teamsters are trying to become a more civil rights-oriented union, organizing immigrants and lower-paid workers to expand their base — including parking lot attendants in Boston — and this case makes it seem as if “picketing as extortion has won the day.’’

“They’re having some difficulty repositioning themselves because cases like this bring up the images of the old Teamsters,’’ he said, referring to the aggressive tactics and mob connections associated with the union under Jimmy Hoffain 1950s and ‘60s. In 2003, the head of Local 25 was brought down by conspiracy, embezzlement, and bribery charges.

News reports about the recent Teamsters’ case “will appear on every bulletin board of every employer in the country that’s being organized by the Teamsters,’’ Chaison said.

And yet, labor leaders say, the victory was essential to preserving workers’ rights — and holding back anti-union forces that might otherwise have been emboldened to challenge unions’ right to picket.

“It’s a good day for democracy in the United States of America,’’ said Brian Lang, president of Unite Here Local 26, the Boston area hospitality workers’ union that frequently pickets businesses, including during a three-week strike of Harvard University dining hall workers last year.

The Massachusetts Nurses Association, whose members went on strike at Tufts Medical Center last month, also applauded the outcome.

“Although some speech and picketing can be uncomfortable, making these expressions illegal would undermine the rights of all and diminish a freedom that many have fought for and cherished as a principal right as an American,’’ spokeswoman Jen Johnson said in a statement.

Despite the ugliness of the Teamsters’ protest, it’s vital that workers have the right to stand up for their rights, said Cambridge civil liberties lawyer Harvey Silverglate.

“Picketing is very often unpleasant,’’ he said. “It’s high pressure, but high pressure is legitimate.’’

Workers, Silverglate added, “have a right to speak very loudly and in a messy fashion.’’

Katie Johnston can be reached at katie.johnston@globe.com.