BROOKLYN, N.Y. — Employers are scared of what Congress and President Obama will do to the U.S. health care system, but “they’re also concerned about doing nothing,” Michael Thompson says.

Employers “are already at the breaking point,” Thompson reported today at a health insurance conference organized by Standard & Poor’s, New York.

The session covered the employer-sponsored health insurance market.

Some policymakers have proposed capping the tax exclusion for employer-sponsored group health coverage, or even eliminating the exclusion. An exclusion cap is unlikely, Thompson said.

But Congress could create a new “public health insurance option” for working-age Americans who are not poor, and it could set up a “health insurance exchange” that would help individuals and small group sponsors shop for standardized health plans. Congress also could impose measures such as a requirement that individuals own health insurance, and a “guaranteed issue” requirement that would eliminate health insurers’ ability to turn away applicants with serious health problems, Thompson said.

A guaranteed issue requirement might work, if accompanied by a successful individual insurance ownership mandate, said David Cordani, president of CIGNA Corp., Philadelphia. “If there’s a mandate that’s not enforced, it becomes a very slippery slope,” he said.

Depending on whether a public health insurance program paid doctors and hospitals relatively high commercial rates, low Medicare rates, or very low Medicaid rates, “it could dramatically destabilize the health care delivery system,” Cordani said.

Sen. Charles Schumer, D-N.Y., has proposed that any government plan pay providers what commercial plans pay, to keep the new public plan from simply shifting costs to commercial plans.

“The challenge is, that’s what they said about Medicare 30 years ago,” Thompson said.