The Republican effort to defund Obamacare threatens a government shutdown at the end of the month. U.S. Rep. Tom Graves, R-Ga., is one lawmaker who believes the dangers of the health care law justify extreme measures.

Over the summer, Graves called the Affordable Care Act "destructive" and a "job killer."

"We need to make every effort to ensure Obamacare is never implemented," he said.

Graves said President Barack Obama’s actions highlight the law’s terminal flaws.

"Something very important has happened since the president did win the election," Graves said on ABC’s This Week . "He himself has amended, delayed, or repealed 19 components of his very own law. So if it's so good for America, then why he is delaying it for his friends in big business?"

We wondered if in fact, Obama has made that many changes in the law.

Graves’ office pointed us to a letter from the Congressional Research Service , the nonpartisan think tank for Congress. The Congressional Research Service review listed 19 times the Affordable Care Act changed since it was passed in 2010. The report counted 14 public laws and five administrative actions that made a variety of modifications to the law.

For the record, we note that a dozen of those adjustments took place before the 2012 election, and not after as Graves said. The timing seems less important than the substance of what was done.

Changes to the Affordable Care Act

Some items on the list qualify as significant in the eyes of the health policy experts we contacted. One of the country’s leading authorities on health care law, Timothy Jost at the Washington and Lee School of Law, pointed to three:

A one-year delay in requiring firms with over 50 workers to provide insurance

Scrapping a long-term care insurance program (for nursing home care, for example) called the CLASS Act

Lifting the requirement on businesses to file a form called a 1099 for a variety of business expenses

The administration acted on its own to delay the employer mandate, explaining that the systems were not in place to implement it. The other two changes came through votes in Congress.

"Congress couldn’t find a way to make the CLASS Act actuarially sound," Jost said, "so they repealed it and put the money elsewhere."

As for the business reporting rule, "businesses said this was a huge burden and Congress responded," Jost said. "There was strong bipartisan support, and you could find the votes to make those sorts of changes."

In addition to those three, a program to create consumer health insurance cooperatives was retained but lost $2.2 billion in funding.

Most of the items on the Congressional Research Service list, however, are less dramatic. Several clarified that certain government health insurance programs would count as coverage under the individual mandate. This included Tricare, which covers the military, and insurance through Veterans Affairs.

Other adjustments extended tax breaks, such as a tax credit for families that adopt a child. There were changes in the Medicaid federal matching formula (to keep money flowing to Louisiana after Katrina), and a tweak to the calculation of income that determines the level of premium subsidies in the insurance exchanges.

Such changes are common in Congress, according to our experts.

"Legislators aren't perfect," said Jost. "They don't get everything right the first time. That’s the nature of the legislative process."

It is also clear that Obama did not drive the majority of the changes. They emerged as Congress worked on various elements of a multi-faceted law. Still, Obama signed off on those changes as part of larger pieces of legislation.

We’ve been here before

Graves’ comments suggest that so many changes to the health care law means it's fundamentally flawed. Actually, major pieces of legislation rarely remain the same as the day the president signs them into law.

The Medicare prescription drug benefit, passed under President George W. Bush, was changed several times after its initial passage.

Both that law and the recent health care law lay a government program on top of a complex private market system, said Ted Marmor, a professor of health policy at Yale University.

"Patches on a patchwork mean making a coherent quilt very difficult," Marmor said.

Even though the country had about two years to get ready for the Medicare drug program, about the same as with Obamacare, some pieces were not in place when the program launched, said Jack Hoadley, a research professor at the Health Policy Institute at Georgetown University.

"States were worried that bunches of people would show up on Jan. 1, 2005, and not be able to get their prescription drugs," Hoadley said. "So some of them started picking up the tab."

Later, Hoadley said, the Bush administration pulled money from another fund to reimburse the states.

The law required insurance plans to set up systems to keep an eye on people who took many different medications. The goal was to make sure the drugs were compatible. The purpose was sensible but as of 2005, the technology wasn’t ready.

"The decision was made that while that requirement was still there, there would be no enforcement until they had time to get things up and running," Hoadley said. "It took several years of saying ‘Lets not focus on this; it’s not the most important thing’."

Our ruling

Graves said Obama "himself has amended, delayed, or repealed 19 components of his very own law." Based on the analysis by the nonpartisan Congressional Research Service, Graves has the right number. However, he simplifies the way that many of those 19 changes came about, and by doing that, makes it seem as though the president were more directly involved.

Graves cited these changes as evidence that the law is fatally flawed but he glossed over the differences among them. Some of the changes were significant and some were technical or tangential to the health care law itself.

The basic number is right but there are lot of details of details missing from Graves' assertion.

We rate the claim Half True.