Obama signed many landmark bills into law during his first two years in office. The main reforms that were passed include the Patient Protection and Affordable Care Act (commonly referred to as the 'Affordable Care Act' or 'Obamacare'), the Dodd–Frank Wall Street Reform and Consumer Protection Act, and the Don't Ask, Don't Tell Repeal Act of 2010. He sponsored a law that increased tax credits for low-income workers, negotiated welfare reform, and promoted increased subsidies for childcare. On June 3, 2008, Senator Obama—along with Senators Tom Carper, Tom Coburn, and John McCain—introduced follow-up legislation: Strengthening Transparency and Accountability in Federal Spending Act of 2008.Obama sponsored legislation that would have required nuclear plant owners to notify state and local authorities of radioactive leaks, but the bill failed to pass in the full Senate after being heavily modified in committee. Regarding tort reform, Obama voted for the Class Action Fairness Act of 2005 and the FISA Amendments Act of 2008, which grants immunity from civil liability to telecommunications companies complicit with NSA warrantless wiretapping operations.