According to U.S. Sen. Lamar Alexander, R-Tennessee, Humana’s decision to pull out of the Obamacare market will leave 40,000 currently-insured people without coverage in Knoxville alone.

That is the crisis that is unfolding in the Volunteer State and elsewhere as the Affordable Care Act continues to collapse like a house of cards.

For much of Tennessee, Humana was the only Obamacare option remaining in 2017, after Blue Cross Blue Shield and United Healthcare pulled out. (United left the exchange altogether, while BCBS stopped offering coverage in Tennessee’s three largest metropolitan counties — Memphis, Nashville and Knoxville — and surrounding areas.)

Even though neighboring Fentress County is not considered part of the Nashville or Knoxville markets and residents there still have access to BCBS through the federal Obamacare exchange, Scott County is considered part of the Knoxville market. Here, options were already few and far between as Affordable Care Act enrollees signed up for their 2017 coverage plans. With Humana being the only option left on the federal exchange, most local providers and facilities are out-of-network — meaning most patients have been faced with the task of switching providers or absorbing enormous out-of-pocket costs. Only two physicians and one pharmacy in Scott County are in the Humana network, according to the federal exchange website. (Almost every local provider and facility was in the BCBS network.)

Now, with Humana also pulling out, the options are going from few to nil. There are other options outside the federal exchange, such as plans offered by Farm Bureau, but that route rules out tax credit subsidies.

Tennessee Insurance Commissioner Julie McPeak said in August that the healthcare exchange is “very near collapse” in the Volunteer State, and it now appears that collapse is imminent.

The blame game in political circles is that Republicans will leave many Americans without healthcare coverage if they repeal Obamacare. Perhaps. But, clearly, the situation in Tennessee is a lesson that many Americans will also be left without coverage if Congress doesn’t act.

Incredibly, there are still some who insist that Congress mustn’t touch Obamacare; that, instead, the status quo must be maintained. It would likely be political suicide for the Republicans who hold the majority in Congress to repeal Obamacare outright, and without replacement, but simply doing nothing — or stalling — are likewise not suitable options.

It is now a necessity that Congress move quickly to reform Obamacare. Otherwise, tens (hundreds?) of thousands of Tennesseans, including some Scott Countians, will be left without coverage when the calendar flips to 2018. For reform to happen, Republicans — including the 3rd District’s Chuck Fleischmann — and Democrats will have to work together, and Congress will have to work with the White House, rather than the stall, delay and obstruction tactics that have been employed by Congress for the past 10 years.

Let’s hope that happens, and sooner rather than later.