New Hampshire Gov. Chris Sununu has signed a bill prohibiting offshore oil and gas drilling in the state's coastal waters.Sununu, a Republican, has opposed President Donald Trump's proposal to expand oil and gas development nationwide. In signing the bill Tuesday, Sununu said the administration has assured him that drilling would not occur off New Hampshire's 18-mile coast, the shortest of any coastal state. But he said the legislation was important to continue the state's tradition of environmental stewardship and protect the coast for future generations.A federal judge ruled this year that Trump exceeded his authority when he ordered that the Arctic and parts of the Atlantic be opened to oil and gas development.Several states, including New Jersey, Maine, New York and Oregon, have enacted similar bans.