Big Labor and Big Business rarely see major public policy issues the same way. But proliferating concerns about the soaring costs — financial and otherwise — of the Affordable Care Act increasingly cross such ideological and economic-interest lines. So it wasn’t a total shock when three top union leaders who had strongly supported the law sounded a belated alarm over its looming consequences.

Presidents James Hoffa (Teamsters), Joseph Hansen (United Food and Commercial Workers) and Donald “D” Taylor (UNITE-HERE, which mainly represents hotel, laundry, warehouse and gambling workers) wrote, in a July 11 letter to Senate Majority Leader Harry Reid and House Minority Leader Nancy Pelosi:

“When you and the President sought our support for the Affordable Care Act (ACA), you pledged that if we liked the health plans we have now, we could keep them. Sadly, that promise is under threat. Right now, unless you and the Obama Administration enact an equitable fix, the ACA will shatter not only our hard-earned health benefits, but destroy the foundation of the 40 hour work week that is the backbone of the American middle class.”

How does “Obamacare” threaten the 40-hour work week?

The letter explains: “The law creates an incentive for employers to keep employees’ work hours below 30 hours a week. Numerous employers have begun to cut workers’ hours to avoid this obligation, and many of them are doing so openly.”

The three labor chiefs also warned that under the law, “non-profit” insurance plans “governed jointly by unions and companies ... will be treated differently and not be eligible for subsidies afforded other citizens.”

President Barack Obama tried to counter the spreading outcry against the law last week. He hailed rebates that some consumers will receive thanks to its requirement that insurers spend at least 80 percent of premiums on direct care for patients.

According to a forbes.com column by Dr. Scott Gottlieb, though, “the reality isn’t quite as rosy” as the president made it sound on that change. That’s because only Americans who purchase insurance on their own — not those who get their coverage through their employers — will get those rebates.

Dr. Gottlieb, a practicing physician and former director of medical policy development at the U.S. Food and Drug Administration, also pointed out that the rule will help “the largest insurers” boost their market shares — “often at the expense of consumers.” And that will limit price competition, thus likely raising health care costs.

Meanwhile, despite numerous waivers and delays in the law’s implementation, it’s already having a negative impact with sweeping stipulations due to take effect by Jan. 1, 2014.

That bad news hit home again last week with the news that Carolina Care, the second largest issuer of individual health insurance plans in South Carolina, is leaving our state by year’s end.

Medical Mutual of Ohio, Carolina Care’s parent company, cited costly Obamacare regulations as the decisive factor in its departure.

South Carolina Sen. Lindsey Graham, who like every other Republican in both chambers of Congress voted against the landmark 2010 legislation, lamented Carolina Care’s impending exit in a written release last week:

“I hate to say I told you so, but I told you so. Every day we see stories like this about Obamacare — rising prices, fewer choices, and more confusion for patients and providers. We now have one less choice for health insurance in South Carolina.”

We also have one more example that the Affordable Care Act is actually quite unaffordable.

But don’t take politicians’ and business bosses’ word for it.

Just ask the labor bosses.