WASHINGTON — In nearly eight years in office, President Barack Obama has sought to reshape the nation with a sweeping assertion of executive authority and a canon of regulations that has inserted the U.S. government more deeply into American life.Obama will leave the White House as one of the most prolific authors of major regulations in presidential history.Blocked for most of his presidency by Congress, Obama has sought to act however he could. In the process, he created the kind of government neither he nor the Republicans wanted — one that depended on bureaucratic bulldozing rather than legislative transparency. But once Obama got the taste for it, he pursued his executive power without apology, and in ways that will shape the presidency for decades to come.The Obama administration in its first seven years finalized 560 major regulations — those classified by the Congressional Budget Office as having particularly significant economic or social impacts. That was nearly 50 percent more than the George W. Bush administration during the comparable period, according to data kept by the regulatory studies center at George Washington University.The new rules built on the legislative victories Obama won during his first two years in office. Those laws — the Affordable Care Act, the Dodd-Frank Act and the $800 billion economic stimulus package— transformed the nation's health care system, curbed the ambitions of the big banks and injected financial support into a creaky economy. But as Republicans increased their control of Capitol Hill, Obama's deep frustration with congressional opposition led to a new approach.Here are some of the most important regulations:Clean power plan: Last year, the Obama administration completed rules requiring the nation's existing power plants to cut, by 2030, emissions of greenhouse gases by 32 percent from 2005 levels. The rules were a central piece of the president's global effort to confront climate change. But a fierce legal challenge has stalled the rules, which are headed to a test in the Supreme Court.Fuel efficiency standards: In the summer of 2012, the administration finished rules to require cars and light trucks to get, on average, nearly 55 miles per gallon by 2025. Critics called the rules costly and unnecessary, but Obama said they would reduce oil consumption by a total of 12 billion barrels by 2025. They survived a legal challenge.Same-sex hospital visitation: After reading about a lesbian social worker who had been kept from the hospital bedside of her partner, Obama issued an order in 2010 directing the creation of regulations to allow such visits. By the next year, new rules required all hospitals that participate in the Medicare and Medicaid programs to allow patients to designate visitors.Passenger bill of rights: After a series of highly publicized cases in which airplane passengers were stranded for hours on the tarmac, the administration in 2009 finished rules requiring airlines to return their planes to the gates within three hours or face steep fines.Rearview cameras: In 2008, Congress passed a measure mandating that all cars have rearview cameras, reacting to tragic stories of children and older people being killed. For years, regulators and industry representatives balked at the cost, but in 2014, the Obama administration completed the regulations, which require backup cameras in cars and light trucks by 2018.Federal workers: In a series of regulatory changes, Obama sought to improve pay and benefits for federal workers and contractors. In 2014, he signed an executive order increasing the minimum wage for federal contract workers to $10.10 per hour from $7.25. The next year, he issued rules requiring up to seven days of paid sick leave for federal contractors. And this year, he increased the number of workers, including federal employees, eligible for overtime.Net neutrality: In early 2015, the Federal Communications Commission, at Obama's urging, issued rules that would regulate Internet companies as utilities. The decision set off a battle among tech companies and digital content providers. This year, a federal court upheld the administration's rules, but the fight is likely to end up in the Supreme Court.Home health aides: The administration imposed rules requiring overtime and minimum wage protections for home health care workers. Opponents filed suit, and won an initial legal victory. But last summer, a federal appeals court reinstated the rules.