Why did health care reform (the PPACA) happen when it did?

Why did health care reform (the PPACA) happen when it did? Couch your answer in terms of the Skocpol and Jacobs book, ‘Health Care Reform and American Politics: What Everyone Needs to Know’, including pertient background information leading up to the passage.

The book can be bought online. Just let me know when I need to pay the extra amount once you’re about to buy it online