But, when the Republicans took control of the House in 2011 and began a series of 32 petulant and futile votes to repeal the ACA, Matheson didn't play along.
The bill he didn't support still had a lot of good things in it, he said, things he didn't think should be summarily taken away from the American people.
Those things include telling the pirates who provide health insurance in this country that they have to sell insurance to everybody, can't take it away when they get sick, have to cover many preventive procedures with no co-pay and must allow families to keep their children on their insurance plan until age 26.
Then, Wednesday, on the 33rd vote, Matheson voted to take all those things away from the American people.
The not completely cynical interpretation of that about-face is that the congressman, with telegenic Republican challenger Mia Love breathing down his neck, was willing to vote to deprive you of what little progress has been made in putting health care within reach of all Americans because he's trying to keep his own government-supplied insurance.
Matheson was one of five House Democrats to break ranks and vote for the latest of several Republican motions to flat repeal, with nothing to take the place of, the ACA. He said he had decided that the law is such an unpopular mess that Congress ought to just tear out those pages and write some new ones.
That vote, for Matheson and for the Republicans, was politics at its worst. Everyone knows the Democratic-majority Senate will not go along.
So all those who voted to repeal the ACA can brag about that without having to face the wrath of voters who might be very upset to learn that insurance companies would once again be allowed to run the most disgraceful business on Earth.
They would instantly go back to taking your money, or your employer's money, when you are well, and making sure you get precious little of it back when you, or your children, are sick.
If your health insurance carrier has another business model than that, I suggest you not buy stock in the company.
Human decency in such operations occurs only when the government makes it a condition of doing business. To do it voluntarily is a betrayal of the managers' fiduciary duties to their stockholders.
The problem with the ACA, of course, is that requiring a little decency is about all it does. The much larger question of making the total cost of providing health care for the whole of the American people, at a cost the whole of the American economy can stomach, has only been scratched.
The solution, of course, is single-payer. Medicare for all. Government power to jawbone down the cost of drugs and surgery and to force an end to unnecessary procedures. Financed by a more progressive form of today's payroll taxes.
Got a better idea?
Neither do the Republicans.
Neither, so far, does Jim Matheson.