We were 15 minutes into our lunchtime discussion when Johnny Isakson got to the crux of what Senate Republicans face this week when they renew their attempt to repeal the Affordable Care Act.

“You have do away with the individual mandate, and then define what the new individual mandate is,” Georgia’s senior senator said.

Put another way: With or without Obamacare, somebody will be telling you and me that we need to purchase health insurance, and that somebody must have the ability to punish us — in the wallet — if we do not.

That’s the price of preserving the ability of those with pre-existing conditions to sign up for health insurance. And that’s a feature of the ACA that Senate Republicans aren’t going ditch. “Getting rid of it ain’t going to happen,” Isakson said.

So come what may, healthier people will be required to bear their share.

The only question is whether the enforcing hammer should be wielded by the Internal Revenue Service, as is currently called for under Obamacare. Or by the private insurance company setting the premium, which would be preferable to Isakson and some – though not all – of his GOP colleagues.

“We’ve got to make sure we have everybody in the system and paying. That’s the biggest hitch,” Isakson said. “We would have had a deal two weeks ago if [Senate leadership], the insurance industry and the administration could figure out that one problem.”

The House version, passed in May, would have allowed insurance companies to slap a one-year, 30 percent premium penalty on those who let their insurance lapse more than 63 days. The second iteration of a Senate bill called for a six-month wait on any claims made by those who let their insurance lapse 63 days.

But Isakson said the shape of the Republican hammer remains ephemeral. “There is no health care bill. It doesn’t exist yet,” he said.

And so the hammer doesn’t, either. “It needs to be big enough to make me say, ‘Now, wait a minute, I better keep my insurance, keep that cash flow going,’” Isakson said.

My meeting with Isakson was about health care, obviously. But it also was an opportunity for the senator to demonstrate that he’s back in the game after a rough six months.

Isakson’s tussle with Parkinson’s disease has been public since 2015. But earlier this year, two back surgeries in less than a month had put him in a wheelchair.

Intense physical therapy allowed the 72-year-old senator to graduate first to a walker, then to a cane – which he parked before mounting the stage unaided on Tuesday at a Fourth of July gathering sponsored by the Cobb County GOP. It was a silent message to those lusting after his job.

Another sign of a renewed Johnny Isakson: He’s planning an August town hall gathering with constituents. Isakson held two via telephone while he recuperated, and a third is in the works. But nationwide, physical gatherings have been scarce among Republican members of Congress faced with defending the repeal of Obamacare.

In Georgia, U.S. Rep. Buddy Carter of Savannah has been the only Republican to host a series of meetings with constituents. And that was back in February.

The specifics of one that features Isakson haven’t been settled. “I don’t want it to be an ambush location, but I also don’t want it to be a phony location,” he said.

But back to health care.

Isakson can’t accurately be described as a Republican swing vote, but he has his requirements – which I asked him to name.

He wants health insurance policies sold across state lines. He wants the number of essential benefits now mandated by Obamacare reduced, in order to promote diversity in policies offered by insurance companies. A competitive health insurance environment is necessary to make a Republican overhaul work, he maintains.

Isakson knows there’s a balance to be struck here. The greatest sin of Obamacare, the senator said, was the “bronze policy” that offered low premiums, but had such a high deductible that it has been nearly useless. A policy-holder might be protected from the catastrophic costs of cancer, only to be bankrupted by a broken leg.

Last week, U.S. Sen. Ted Cruz, R-Texas, and his allies pitched an idea for Republican consideration: Allow insurance companies to sell any kind of health insurance policy they want — as long as they also sell at least one plan that meets ACA requirements.

I asked Isakson about the idea. He didn’t dismiss it. “You could stay in business offering a policy nobody would buy, and satisfy the law,” he said.

But Isakson grew less enamored as he went on. “If it’s a crappy policy, it doesn’t do anything to solve anything. In fact, it’s kind of like what Obama sold everybody on the bronze policy,” he said.

Insurance companies would get their premiums, but illnesses and conditions that were uncovered would still leave hospitals holding the bag.

Hospitals are Isakson’s focus. The Senate Republican drafts so far would curtail the expansion of Medicaid, to the point that Congressional Budget Office scoring says 22 million Americans would lose coverage over the next decade. Gov. Nathan Deal never accepted the federal cash that would have allowed expansion in Georgia, so many state hospitals remain in a precarious financial position – especially in rural portions of the state.

When Obamcare was passed, federal payments to hospitals tasked with heavy loads of charity work – such as Grady Memorial in Atlanta and Memorial Health in Savannah — were to be phased out. Medicaid expansion was to have solved the problem. Those extra payments disappear in four-and-a-half years.

Isakson wants those payments restored — permanently. “America’s not going to be a country that leaves its poor on the doorsteps of hospitals, dying because they can’t get treatment. We’re smart enough to figure something out.

“There’ll be some contribution for hospitals that take on the charity patients, and I think a lot of it will come from not-for-profits,” Isakson said.

The senator was speaking of those hospitals that are public and non-profit in name, but are operated by private management companies that do very well, thank you. We have them here in Georgia, but it’s a national phenomenon.

For the last several years, the Legislature has approved a “bed tax” paid by all Georgia hospitals in order to build a pool of cash that can be used by the state to draw down matching federal Medicaid dollars.

It sounds like Isakson’s thinking of a nationalized version of this.

The deal-making begins on Tuesday.