On Saturday afternoon, he announced his decision to oppose the $940 billion package because he said it is "too expensive, contains too many special deals, does not contain health care costs and will result in increases in health insurance premiums."
Democratic leaders take issue with each of those claims, arguing that their bill gives American workers more security, helps the poor, reduces the debt and makes insurance more affordable for businesses and the government.
Matheson's no vote means that every federal lawmaker from Utah will oppose health reform, but unlike his Republican colleagues, Matheson said the decision was far from easy.
"I definitely struggled with it," he told The Salt Lake Tribune . "It is such an important issue and there were definitely components of this legislation that I think we all support."
Matheson cited some of the insurance industry reforms, such as the removal of lifetime caps on benefits or the prohibition against denying someone insurance due to a pre-existing condition. He also liked the financial estimate that showed the bill reducing the deficit by $138 billion in the next 10 years.
But reducing the government's debt is not the same as controlling rising costs for consumers, by which he means insurance premiums and doctors' costs.
"I think we've got to take some very tough steps to try to get control of these out of control costs and I don't think the bill goes far enough in that way," he said.
Matheson didn't give specific suggestions about what could lower those costs, though he did praise an idea that remains in the health reform bill the House is expected to vote on Sunday -- a tax on high-end plans, meant to dissuade people from overusing the medical system.
He believes the Democrats' bill puts too much emphasis on expanding coverage to 32 million uninsured and not enough on reforming the financial incentives in the current system, saying if the bill leads to more people accessing overly-expensive care it will leave the nation worse off.
Matheson's critics, be they upset health reform supporters or Republicans who like his health stance but still want him lose in November, insinuate that his vote came down to more than a concern about costs.
"I'm just devastated," said Judi Hilman, an advocate with the Utah Health Policy Project, which organized a citizen lobbying effort to convince Matheson to support the bill. "He has allowed politics to take over the decision making in this instance and that is really unfortunate."
She called his reasons for voting against the bill "disingenuous."
"This is a slap in the face to those of us who have worked for most of our lives to reach this critical moment in our nation's history," Hilman said.
Matheson's decision came only a few hours after President Barack Obama made a spirited pitch to the House Democratic caucus, acknowledging that a vote for health reform may be politically difficult for some.
"Don't do it for me. Don't do it for Nancy Pelosi or Harry Reid. Do it for all those people out there who are struggling," Obama said.
Matheson is a conservative Blue Dog Democrat in a district that leans Republican, which makes him a constant target of the GOP. Republicans have vowed to make health reform the biggest campaign issue in 2010, believing the public is skeptical of the bill and dislikes the process Democrats used to get it through Congress.
Despite his decision against the bill for reasons they essentially agree with, GOP leaders slammed Matheson on Saturday for taking so long to make a stand.
"With his usual finger to the wind approach, Jim Matheson let his decision on the government takeover of health care be a cliffhanger when it should have been a no-brainer," said Joanna Burgos, spokeswoman for the National Republican Congressional Committee.
Utah Republican Party Chairman Dave Hansen claimed Matheson waited until the state's filing deadline passed on Friday to avoid a high-profile challenger, be it a Democrat or Republican.
Matheson categorically denies that he considered the political ramifications of his decision and said he wasn't trying to duck any potential campaign opponents.
He said he waited to announce his vote for a much more simple reason. The final version was only released on Thursday.
"I like to see the bill before I make my final decision," he said.