Democratic presidential candidate Bernie Sanders has been relentless in his attacks on Verizon (VZ) - Get Report  over the past few weeks. And believe it or not, the criticisms of the self-described democratic socialist could hurt the company where it matters most: the balance sheet.

Verizon CFO Fran Shammo warned in an investor conference call Thursday that a bitter labor contract dispute with nearly 40,000 of its employees might weigh on the company's earnings.

"Given the status of our labor contract negotiations, there will be pressure on earnings in the second quarter due to the timing of cost reductions," he said. "Depending on the progress of negotiations, we may need to update the full-year guidance at a later time."

This wouldn't be the first time a labor dispute has hurt Verizon's bottom line. In 2011, the combination of heavy storms and a two-week strike cost it $250 million. And depending on the length of the strike, the impact for Verizon's earnings could grow. 

"Expectations are that [the labor dispute] will be a one to two cent drag to earnings for 2Q," said Macquarie analyst Amy Yong in a phone interview Friday afternoon. "Obviously if the strike is prolonged, then it could be a bigger impact."

James Moorman, analyst at D.A. Davidson & Co., noted in an analyst note Friday that the strike could delay cost-cutting measures the company has promised. "While we continue to believe the strike will have a minimal impact beyond some installation delays, cost-cutting was expected to help offset the loss of profits from the wireline properties sold to Frontier," he wrote, adding that the firm has cut its second-quarter earnings per share estimate for the company as well.

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Sanders has thrown his full weight behind workers representing the Communications Workers of America (CWA) and the International Brotherhood of Electrical Workers (IBEW) who on April 13 went on strike at Verizon. He attended two rallies with Verizon employees while campaigning in New York City and has continued to poke at Verizon, attacking CEO Lowell McAdam and accusing the company of avoiding taxes.

Thursday evening, the Sanders campaign sent an email to supporters lambasting McAdam and Verizon yet again.

"The CEO of Verizon makes almost $20 million a year in compensation. He leads one of the most profitable companies in the country," the email reads. "Yet Verizon wants to take away employees' health benefits. Verizon wants to outsource decent-paying jobs. Verizon wants to avoid paying federal income tax. And right now, Verizon is refusing to sit down and negotiate a fair contract with its employees. In other words, Verizon is just another major American corporation trying to destroy the lives of working Americans."

The Sanders camp has also launched a petition in support of Verizon workers.

In continuing to fan the flames of the fire, the Vermont senator might be prolonging the dispute. And that will hit the company's bottom line.

To be sure, the standoff could wind up being a good thing for Verizon if the dispute works out in its favor. "The ongoing labor contract negotiations could present a silver lining in more flexible labor practices and lower health care liabilities, particularly for retirees," Oppenheimer analyst Tim Horan wrote in a note Thursday.

Thus far, the fight is showing no signs of immediate resolution. Talks between the sides in a Tuesday session were largely unproductive. Perhaps not helping in quickly resolving the dispute, Sanders' involvement appears to have emboldened workers.

"Bernie Sanders is highlighting the importance of this strike and this fight as an example of what's wrong in America today, where greedy corporations can outsource a contract out and offshore jobs, even then they're booking stunning profits of over $1.5 billion a month," said Pete Sikora, research economist and strike mobilization coordinator at CWA-District 1, adding that fellow Democratic contender Hillary Clinton and former President Bill Clinton had visited picket lines as well.

Still, it is Sanders who has lifted the dispute, which is largely focused on the East Coast, to the national stage -- and kept it there. "He's just been tremendous," Sikora said.

Gary Chaison, professor of industrial relations at Clark University, noted in an email that the Verizon strike and Sanders campaign are representative of a larger tsunami of discontent sweeping the American workforce. 

"The Verizon strike is emblematic of all the problems that unions and the economy face and that Bernie Sanders talks so much about and gains so much support on," he said.

A Verizon spokesman declined to comment on the current state of the labor dispute or Sanders' continued involvement in it. He pointed to an April 13 op-ed penned by McAdam, in which he calls what he says are the senator's "uninformed" views "contemptible." The piece was inspired by an editorial written by Jeff Immelt, CEO of another of Sanders' favorite targets, General Electric.

"Jeff [Immelt] made it clear [in his editorial] that Socialists have never been big fans of GE," said TheStreet's Jim Cramer, who owns GE in his Action Alerts PLUS Charitable Trust Portfolio. GE employs 125,000 Americans, 1,000 of whom are at the company's aviation plant in Vermont. To boot, the aviation segment was the best-performing and fastest-growing segment at the company.

Perhaps the confusion lies in the motive, and for Sanders one obvious place to look is his campaign war chest. After signing the Verizon petition on his website, supporters are taken to a separate website prompting them to donate to his campaign. The Sanders camp did not respond to request for comment.