What is President Obama important contributions?

Most observers would report that President's Obama's major contribution in office during his first term was the Patient Protection and Affordable Care Act, PPACA for short, commonly referred to as "Obamacare". This extends health care to millions of Americans, including those with pre-existing conditions. But some people might also say his major contribution was to rescue to auto industry, or to end the US involvement in Iraq and bring most of the troops home.