If you stop and shop at Stop & Shop this weekend in Connecticut, Massachusetts or Rhode Island, there's a good chance you'll see some of their 34,000 employees outside, greeting employees with flyers.

The reason: Their contract expires at midnight Saturday going into Sunday, and members of United Food and Confectionery Workers local are looking for support as they head to a possible strike.

Not just the grocery business but the gas business could face labor strife and disruption as well. National Grid’s contract with 800 natural gas utility workers around Boston expires 24 hours later, at midnight Sunday going into Monday, and those workers have already unanimously authorized Steelworkers Local 12003 leaders to call a strike if they see fit.

Both situations involve some issues unique to each company but a common theme, the same theme that dominates so much of the presidential campaign debate this year: Income inequality and a middle class losing ground as corporate America and its leaders seek to grow ever richer.

At Stop & Shop, "We're asking them to call the company, say they stand with the workers," said Jim Carvalho, political director for UFCW Local 1445, which represents workers at Stop & Shops in the Boston and Worcester areas and Essex County, Massachusetts. It's negotiating alongside four other UFCW locals – 328, 371, 919, and 1459 – across southern New England.

Carvalho said union negotiators have been facing proposals from Stop & Shop to set up a two-tier wage system offering lower pay and benefits to new employees.

"They're looking to have cuts to the pensions, increased costs to the health care, inadequate wage increases" and other contract givebacks, Carvalho said.

Stop & Shop has already been advertising to hire replacement workers if there is a strike.

Stop & Shop said it’s confident there will be a deal, not a strike. In a statement, the company said: "We have always reached a fair agreement with these unions, and do not expect this time to be any different. To be very clear, and contrary to the leaflets being distributed by the unions, Stop & Shop is not proposing to freeze wages. In fact, Stop & Shop is offering to give all of our Associates increased pay."

"In addition," the company said, "Stop & Shop has offered to continue to provide associates generous paid time off and rich health care benefits with Associate premiums that are significantly less than market averages. Our offer will also maintain our current contribution level to their industry leading defined-benefit pension plan. We look forward to reaching an agreement that reflects the economic needs of our Associates and the competitive realities facing our company."

At National Grid, one of the most bitterly contested issues is the company’s desire to outsource more maintenance work, both on its gas distribution network and inside customers’ homes, to lower-paid contract workers. Local 12003 is also trying to undo past agreements to have non-union workers mark gas line locations under Dig Safe for construction work, a move they say has compromised safety.

"They have a CEO that makes over $7 million a year, and they’re worried about the cost of keeping the public safe – they think it’s too expensive to keep the public safe," Local 12033 president Joe Kirylo said in an interview Friday afternoon during a break in contract negotiations.

"Nobody wants a labor dispute. We don't want a labor dispute. We want to work through this," Kirylo said. But the union - which went through a six-month strike in 1993 against predecessor Boston Gas Co. – has unanimously voted to authorize leaders to call a strike, which is not uncommon in utility contract negotiations.

National Grid spokeswoman Mary-Leah Assad said: "The company is committed to bargaining in good faith and looks forward to reaching a fair and equitable contract for all parties. The safety of our employees, customers and communities is our first priority and will continue throughout this process."

Besides safety questions, as with Stop & Shop, good union pay and benefits in an era of wage stagnation and soaring health-insurance costs are on the line at National Grid.

"It's a fight for ourselves, it's a fight for the public, and I'll be honest with you, it's a fight for the middle class in general," Kirylo said.

With videographer Aaron Strader