Limit damage of Obamacare 'coercion': GOP senator

The last thing anybody wants is a shutdown: Sen. Johnson

Republican warnings about Obamacare are no longer theoretical, Sen. Ron Johnson told CNBC on Monday. Americans are starting to feel the "real disaster" of this health-care law, the Wisconsin Republican added.

But it's going to be difficult now to repeal the Affordable Care Act, because "it's been implemented, it's structurally in place," Johnson said in a "Squawk Box" interview.

"I think the responsible thing to do is ... limit the damage," he said, claiming that Obamacare is about "coercion" not choice.

(Read more: Left out: Insurance agents' struggle with Obamacare)

Johnson said there's not a lot that can be done for the people whose current health plans have been canceled because they didn't meet the new, wider coverage requirements of Obamacare.

But it's not too late to help people keep their insurance through their employer, he continued. "Those health-care plans can be preserved by reducing or eliminating the coverage mandates that are driving up the cost of health care."

(Read more: Obamacare: An unevenplaying field for hospitals)

"If you want a strong social safety net," he said, "we should make sure every American has catastrophic care plan" and then start moving toward a free-market based solution for wider coverage choices.

Johnson also takes issue with one of the cornerstones of Obamacare, which is that young people who are generally healthier need to buy into the system to pay for coverage that they'll be less likely to use as much as their sick and older counterparts.

(Read more: Obamacare 'perfect storm'—Feds reveal 10 percent error rate)

"When you can buy insurance regardless of pre-existing conditions, why buy it ahead of time?" he asked, saying that even the tax penalties for not purchasing coverage for next year are small compared to the cost of making the monthly payments for insurance.

As for the upcoming mid-term elections in Congress next year, Johnson said that because of the disastrous implementation of the health-care law things look "pretty optimistic" for Republicans.

By CNBC's Matthew J. Belvedere. Follow him on Twitter @Matt_SquawkCNBC.