But "the 'bare county' phenomenon creates incredible pressure for us to provide a solution, so people can have health insurance," Kaine said. "We will provide a vigorous public option to allow people to buy into Medicare."

The Hearing

Thursday's individual health market hearing was the last hearing in a series of four individual health hearings organized by the Senate HELP Committee.

The committee has posted a package of hearing materials, including a video recording and written versions of the witnesses' testimony, here.

In addition to Ruiz-Moss, the witness list for today's hearing included Dr. Manny Sethi, an orthopedic trauma surgeon from Nashville, Tennessee; Dr. Susan Turney, chief executive officer of Marshfield Clinic Health System Inc. in Marshfield, Wisconsin; Christina Postolowski, the Rocky Mountain regional director for Young Invincibles; and Raymond Farmer, the director of the South Carolina Department of Insurance and the secretary-treasurer at the National Association of Insurance Commissioners.

The witnesses asked Congress to keep the current Affordable Care Act cost-sharing reduction subsidy program in place in 2018 and 2019, and to provide a replacement for the ACA reinsurance program, a program that was designed to expire at the end of 2016.

Ruiz-Moss, who is a Denver-based vice president in the individual market segment at Anthem Inc., talked in the written version of his testimony about health insurers' need for regulatory stability.

Insurers now face basic questions about rules and funding sources for 2018, Ruiz-Moss said.

Even in calmer times, "Health plans serving consumers in the individual market are regulated by two, and, in some cases, three or four separate government entities with varying requirements, mandates and timelines to follow," Ruiz-Moss said.

Implementing even small changes in individual health rules can be tremendously burdensome, he said.

Medicare Buy-In Program

Kaine was Hillary Clinton's vice presidential running mate in 2016. Before he entered the Senate, he was governor of Virginia. While he was the governor of Virginia, he appointed Marilyn Tavenner to be his secretary of Health and Human Services. Tavenner is now the president of America's Health Insurance Plans, a major health insurance company trade group.

At press time, Kaine was not on the list of cosponsors of S. 1804, Sen. Bernie Sanders' "Medicare for All" single-payer health insurance bill.

In 2016, Kaine held back from cosponsoring Senate Resolution 561, a bill that expressed support for the idea of setting up a public health insurance plan that would be open to everyone in the United States.

Kaine said at the hearing that he personally does support the idea of letting all Americans buy into Medicare, but that he does not have the votes to make that happen.

Today, Kaine said, he does not have the votes to create a universal Medicare buy-in program.

If, however, some counties lack commercial individual health insurance options in 2018, "I will get the votes," Kaine said.

Any Medicare buy-in program created would probably be broad, and not aimed only at uninsurable people, or only at people in counties without commercial individual health insurance options, Kaine said.

The Medicare buy-in program would be broad partly because the program designers would face the same kind of actuarial pressure that commercial health plan designers face to make the program risk pool as broad as possible, Kaine said.